2012-09-27 04:11:01 +00:00
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/* NG4memcpy.S: Niagara-4 optimized memcpy.
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*
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* Copyright (C) 2012 David S. Miller (davem@davemloft.net)
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*/
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#ifdef __KERNEL__
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#include <asm/visasm.h>
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#include <asm/asi.h>
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#define GLOBAL_SPARE %g7
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#else
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#define ASI_BLK_INIT_QUAD_LDD_P 0xe2
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#define FPRS_FEF 0x04
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/* On T4 it is very expensive to access ASRs like %fprs and
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* %asi, avoiding a read or a write can save ~50 cycles.
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*/
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#define FPU_ENTER \
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rd %fprs, %o5; \
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andcc %o5, FPRS_FEF, %g0; \
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be,a,pn %icc, 999f; \
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wr %g0, FPRS_FEF, %fprs; \
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999:
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#ifdef MEMCPY_DEBUG
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#define VISEntryHalf FPU_ENTER; \
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clr %g1; clr %g2; clr %g3; clr %g5; subcc %g0, %g0, %g0;
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#define VISExitHalf and %o5, FPRS_FEF, %o5; wr %o5, 0x0, %fprs
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#else
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#define VISEntryHalf FPU_ENTER
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#define VISExitHalf and %o5, FPRS_FEF, %o5; wr %o5, 0x0, %fprs
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#endif
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#define GLOBAL_SPARE %g5
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#endif
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#ifndef STORE_ASI
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#ifndef SIMULATE_NIAGARA_ON_NON_NIAGARA
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#define STORE_ASI ASI_BLK_INIT_QUAD_LDD_P
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#else
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#define STORE_ASI 0x80 /* ASI_P */
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#endif
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#endif
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sparc64: Fix FPU register corruption with AES crypto offload.
The AES loops in arch/sparc/crypto/aes_glue.c use a scheme where the
key material is preloaded into the FPU registers, and then we loop
over and over doing the crypt operation, reusing those pre-cooked key
registers.
There are intervening blkcipher*() calls between the crypt operation
calls. And those might perform memcpy() and thus also try to use the
FPU.
The sparc64 kernel FPU usage mechanism is designed to allow such
recursive uses, but with a catch.
There has to be a trap between the two FPU using threads of control.
The mechanism works by, when the FPU is already in use by the kernel,
allocating a slot for FPU saving at trap time. Then if, within the
trap handler, we try to use the FPU registers, the pre-trap FPU
register state is saved into the slot. Then at trap return time we
notice this and restore the pre-trap FPU state.
Over the long term there are various more involved ways we can make
this work, but for a quick fix let's take advantage of the fact that
the situation where this happens is very limited.
All sparc64 chips that support the crypto instructiosn also are using
the Niagara4 memcpy routine, and that routine only uses the FPU for
large copies where we can't get the source aligned properly to a
multiple of 8 bytes.
We look to see if the FPU is already in use in this context, and if so
we use the non-large copy path which only uses integer registers.
Furthermore, we also limit this special logic to when we are doing
kernel copy, rather than a user copy.
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-10-15 02:37:58 +00:00
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#if !defined(EX_LD) && !defined(EX_ST)
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#define NON_USER_COPY
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#endif
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2012-09-27 04:11:01 +00:00
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#ifndef EX_LD
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#define EX_LD(x) x
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#endif
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sparc64: fix FP corruption in user copy functions
Short story: Exception handlers used by some copy_to_user() and
copy_from_user() functions do not diligently clean up floating point
register usage, and this can result in a user process seeing invalid
values in floating point registers. This sometimes makes the process
fail.
Long story: Several cpu-specific (NG4, NG2, U1, U3) memcpy functions
use floating point registers and VIS alignaddr/faligndata to
accelerate data copying when source and dest addresses don't align
well. Linux uses a lazy scheme for saving floating point registers; It
is not done upon entering the kernel since it's a very expensive
operation. Rather, it is done only when needed. If the kernel ends up
not using FP regs during the course of some trap or system call, then
it can return to user space without saving or restoring them.
The various memcpy functions begin their FP code with VISEntry (or a
variation thereof), which saves the FP regs. They conclude their FP
code with VISExit (or a variation) which essentially marks the FP regs
"clean", ie, they contain no unsaved values. fprs.FPRS_FEF is turned
off so that a lazy restore will be triggered when/if the user process
accesses floating point regs again.
The bug is that the user copy variants of memcpy, copy_from_user() and
copy_to_user(), employ an exception handling mechanism to detect faults
when accessing user space addresses, and when this handler is invoked,
an immediate return from the function is forced, and VISExit is not
executed, thus leaving the fprs register in an indeterminate state,
but often with fprs.FPRS_FEF set and one or more dirty bits. This
results in a return to user space with invalid values in the FP regs,
and since fprs.FPRS_FEF is on, no lazy restore occurs.
This bug affects copy_to_user() and copy_from_user() for NG4, NG2,
U3, and U1. All are fixed by using a new exception handler for those
loads and stores that are done during the time between VISEnter and
VISExit.
n.b. In NG4memcpy, the problematic code can be triggered by a copy
size greater than 128 bytes and an unaligned source address. This bug
is known to be the cause of random user process memory corruptions
while perf is running with the callgraph option (ie, perf record -g).
This occurs because perf uses copy_from_user() to read user stacks,
and may fault when it follows a stack frame pointer off to an
invalid page. Validation checks on the stack address just obscure
the underlying problem.
Signed-off-by: Rob Gardner <rob.gardner@oracle.com>
Signed-off-by: Dave Aldridge <david.j.aldridge@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-23 06:24:49 +00:00
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#ifndef EX_LD_FP
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#define EX_LD_FP(x) x
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#endif
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2012-09-27 04:11:01 +00:00
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#ifndef EX_ST
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#define EX_ST(x) x
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#endif
|
sparc64: fix FP corruption in user copy functions
Short story: Exception handlers used by some copy_to_user() and
copy_from_user() functions do not diligently clean up floating point
register usage, and this can result in a user process seeing invalid
values in floating point registers. This sometimes makes the process
fail.
Long story: Several cpu-specific (NG4, NG2, U1, U3) memcpy functions
use floating point registers and VIS alignaddr/faligndata to
accelerate data copying when source and dest addresses don't align
well. Linux uses a lazy scheme for saving floating point registers; It
is not done upon entering the kernel since it's a very expensive
operation. Rather, it is done only when needed. If the kernel ends up
not using FP regs during the course of some trap or system call, then
it can return to user space without saving or restoring them.
The various memcpy functions begin their FP code with VISEntry (or a
variation thereof), which saves the FP regs. They conclude their FP
code with VISExit (or a variation) which essentially marks the FP regs
"clean", ie, they contain no unsaved values. fprs.FPRS_FEF is turned
off so that a lazy restore will be triggered when/if the user process
accesses floating point regs again.
The bug is that the user copy variants of memcpy, copy_from_user() and
copy_to_user(), employ an exception handling mechanism to detect faults
when accessing user space addresses, and when this handler is invoked,
an immediate return from the function is forced, and VISExit is not
executed, thus leaving the fprs register in an indeterminate state,
but often with fprs.FPRS_FEF set and one or more dirty bits. This
results in a return to user space with invalid values in the FP regs,
and since fprs.FPRS_FEF is on, no lazy restore occurs.
This bug affects copy_to_user() and copy_from_user() for NG4, NG2,
U3, and U1. All are fixed by using a new exception handler for those
loads and stores that are done during the time between VISEnter and
VISExit.
n.b. In NG4memcpy, the problematic code can be triggered by a copy
size greater than 128 bytes and an unaligned source address. This bug
is known to be the cause of random user process memory corruptions
while perf is running with the callgraph option (ie, perf record -g).
This occurs because perf uses copy_from_user() to read user stacks,
and may fault when it follows a stack frame pointer off to an
invalid page. Validation checks on the stack address just obscure
the underlying problem.
Signed-off-by: Rob Gardner <rob.gardner@oracle.com>
Signed-off-by: Dave Aldridge <david.j.aldridge@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-23 06:24:49 +00:00
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#ifndef EX_ST_FP
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#define EX_ST_FP(x) x
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#endif
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2012-09-27 04:11:01 +00:00
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#ifndef EX_RETVAL
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#define EX_RETVAL(x) x
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#endif
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#ifndef LOAD
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#define LOAD(type,addr,dest) type [addr], dest
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#endif
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#ifndef STORE
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#ifndef MEMCPY_DEBUG
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#define STORE(type,src,addr) type src, [addr]
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#else
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#define STORE(type,src,addr) type##a src, [addr] %asi
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#endif
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#endif
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#ifndef STORE_INIT
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#define STORE_INIT(src,addr) stxa src, [addr] STORE_ASI
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#endif
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#ifndef FUNC_NAME
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#define FUNC_NAME NG4memcpy
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#endif
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#ifndef PREAMBLE
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#define PREAMBLE
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#endif
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#ifndef XCC
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#define XCC xcc
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#endif
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.register %g2,#scratch
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.register %g3,#scratch
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.text
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.align 64
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.globl FUNC_NAME
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.type FUNC_NAME,#function
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FUNC_NAME: /* %o0=dst, %o1=src, %o2=len */
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#ifdef MEMCPY_DEBUG
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wr %g0, 0x80, %asi
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#endif
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srlx %o2, 31, %g2
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cmp %g2, 0
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tne %XCC, 5
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PREAMBLE
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mov %o0, %o3
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brz,pn %o2, .Lexit
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cmp %o2, 3
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ble,pn %icc, .Ltiny
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cmp %o2, 19
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ble,pn %icc, .Lsmall
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or %o0, %o1, %g2
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cmp %o2, 128
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bl,pn %icc, .Lmedium
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nop
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.Llarge:/* len >= 0x80 */
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/* First get dest 8 byte aligned. */
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sub %g0, %o0, %g1
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and %g1, 0x7, %g1
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brz,pt %g1, 51f
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sub %o2, %g1, %o2
|
2012-09-28 20:08:22 +00:00
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2012-09-27 04:11:01 +00:00
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1: EX_LD(LOAD(ldub, %o1 + 0x00, %g2))
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add %o1, 1, %o1
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subcc %g1, 1, %g1
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add %o0, 1, %o0
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bne,pt %icc, 1b
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EX_ST(STORE(stb, %g2, %o0 - 0x01))
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51: LOAD(prefetch, %o1 + 0x040, #n_reads_strong)
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LOAD(prefetch, %o1 + 0x080, #n_reads_strong)
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LOAD(prefetch, %o1 + 0x0c0, #n_reads_strong)
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LOAD(prefetch, %o1 + 0x100, #n_reads_strong)
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LOAD(prefetch, %o1 + 0x140, #n_reads_strong)
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LOAD(prefetch, %o1 + 0x180, #n_reads_strong)
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LOAD(prefetch, %o1 + 0x1c0, #n_reads_strong)
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LOAD(prefetch, %o1 + 0x200, #n_reads_strong)
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/* Check if we can use the straight fully aligned
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* loop, or we require the alignaddr/faligndata variant.
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*/
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andcc %o1, 0x7, %o5
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bne,pn %icc, .Llarge_src_unaligned
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sub %g0, %o0, %g1
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/* Legitimize the use of initializing stores by getting dest
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* to be 64-byte aligned.
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*/
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and %g1, 0x3f, %g1
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brz,pt %g1, .Llarge_aligned
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sub %o2, %g1, %o2
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2012-09-28 20:08:22 +00:00
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2012-09-27 04:11:01 +00:00
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1: EX_LD(LOAD(ldx, %o1 + 0x00, %g2))
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add %o1, 8, %o1
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subcc %g1, 8, %g1
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add %o0, 8, %o0
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bne,pt %icc, 1b
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EX_ST(STORE(stx, %g2, %o0 - 0x08))
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.Llarge_aligned:
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/* len >= 0x80 && src 8-byte aligned && dest 8-byte aligned */
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andn %o2, 0x3f, %o4
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sub %o2, %o4, %o2
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1: EX_LD(LOAD(ldx, %o1 + 0x00, %g1))
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add %o1, 0x40, %o1
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EX_LD(LOAD(ldx, %o1 - 0x38, %g2))
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subcc %o4, 0x40, %o4
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EX_LD(LOAD(ldx, %o1 - 0x30, %g3))
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EX_LD(LOAD(ldx, %o1 - 0x28, GLOBAL_SPARE))
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EX_LD(LOAD(ldx, %o1 - 0x20, %o5))
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EX_ST(STORE_INIT(%g1, %o0))
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add %o0, 0x08, %o0
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EX_ST(STORE_INIT(%g2, %o0))
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add %o0, 0x08, %o0
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EX_LD(LOAD(ldx, %o1 - 0x18, %g2))
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|
EX_ST(STORE_INIT(%g3, %o0))
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add %o0, 0x08, %o0
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EX_LD(LOAD(ldx, %o1 - 0x10, %g3))
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EX_ST(STORE_INIT(GLOBAL_SPARE, %o0))
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add %o0, 0x08, %o0
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EX_LD(LOAD(ldx, %o1 - 0x08, GLOBAL_SPARE))
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|
EX_ST(STORE_INIT(%o5, %o0))
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|
add %o0, 0x08, %o0
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EX_ST(STORE_INIT(%g2, %o0))
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|
add %o0, 0x08, %o0
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|
EX_ST(STORE_INIT(%g3, %o0))
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|
|
add %o0, 0x08, %o0
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|
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|
EX_ST(STORE_INIT(GLOBAL_SPARE, %o0))
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|
add %o0, 0x08, %o0
|
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|
bne,pt %icc, 1b
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|
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|
LOAD(prefetch, %o1 + 0x200, #n_reads_strong)
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|
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|
|
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|
|
membar #StoreLoad | #StoreStore
|
|
|
|
|
|
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|
brz,pn %o2, .Lexit
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|
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|
cmp %o2, 19
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|
|
|
|
ble,pn %icc, .Lsmall_unaligned
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|
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|
nop
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|
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|
ba,a,pt %icc, .Lmedium_noprefetch
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|
|
.Lexit: retl
|
|
|
|
|
mov EX_RETVAL(%o3), %o0
|
|
|
|
|
|
|
|
|
|
.Llarge_src_unaligned:
|
sparc64: Fix FPU register corruption with AES crypto offload.
The AES loops in arch/sparc/crypto/aes_glue.c use a scheme where the
key material is preloaded into the FPU registers, and then we loop
over and over doing the crypt operation, reusing those pre-cooked key
registers.
There are intervening blkcipher*() calls between the crypt operation
calls. And those might perform memcpy() and thus also try to use the
FPU.
The sparc64 kernel FPU usage mechanism is designed to allow such
recursive uses, but with a catch.
There has to be a trap between the two FPU using threads of control.
The mechanism works by, when the FPU is already in use by the kernel,
allocating a slot for FPU saving at trap time. Then if, within the
trap handler, we try to use the FPU registers, the pre-trap FPU
register state is saved into the slot. Then at trap return time we
notice this and restore the pre-trap FPU state.
Over the long term there are various more involved ways we can make
this work, but for a quick fix let's take advantage of the fact that
the situation where this happens is very limited.
All sparc64 chips that support the crypto instructiosn also are using
the Niagara4 memcpy routine, and that routine only uses the FPU for
large copies where we can't get the source aligned properly to a
multiple of 8 bytes.
We look to see if the FPU is already in use in this context, and if so
we use the non-large copy path which only uses integer registers.
Furthermore, we also limit this special logic to when we are doing
kernel copy, rather than a user copy.
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-10-15 02:37:58 +00:00
|
|
|
#ifdef NON_USER_COPY
|
|
|
|
|
VISEntryHalfFast(.Lmedium_vis_entry_fail)
|
|
|
|
|
#else
|
|
|
|
|
VISEntryHalf
|
|
|
|
|
#endif
|
2012-09-27 04:11:01 +00:00
|
|
|
andn %o2, 0x3f, %o4
|
|
|
|
|
sub %o2, %o4, %o2
|
|
|
|
|
alignaddr %o1, %g0, %g1
|
|
|
|
|
add %o1, %o4, %o1
|
sparc64: fix FP corruption in user copy functions
Short story: Exception handlers used by some copy_to_user() and
copy_from_user() functions do not diligently clean up floating point
register usage, and this can result in a user process seeing invalid
values in floating point registers. This sometimes makes the process
fail.
Long story: Several cpu-specific (NG4, NG2, U1, U3) memcpy functions
use floating point registers and VIS alignaddr/faligndata to
accelerate data copying when source and dest addresses don't align
well. Linux uses a lazy scheme for saving floating point registers; It
is not done upon entering the kernel since it's a very expensive
operation. Rather, it is done only when needed. If the kernel ends up
not using FP regs during the course of some trap or system call, then
it can return to user space without saving or restoring them.
The various memcpy functions begin their FP code with VISEntry (or a
variation thereof), which saves the FP regs. They conclude their FP
code with VISExit (or a variation) which essentially marks the FP regs
"clean", ie, they contain no unsaved values. fprs.FPRS_FEF is turned
off so that a lazy restore will be triggered when/if the user process
accesses floating point regs again.
The bug is that the user copy variants of memcpy, copy_from_user() and
copy_to_user(), employ an exception handling mechanism to detect faults
when accessing user space addresses, and when this handler is invoked,
an immediate return from the function is forced, and VISExit is not
executed, thus leaving the fprs register in an indeterminate state,
but often with fprs.FPRS_FEF set and one or more dirty bits. This
results in a return to user space with invalid values in the FP regs,
and since fprs.FPRS_FEF is on, no lazy restore occurs.
This bug affects copy_to_user() and copy_from_user() for NG4, NG2,
U3, and U1. All are fixed by using a new exception handler for those
loads and stores that are done during the time between VISEnter and
VISExit.
n.b. In NG4memcpy, the problematic code can be triggered by a copy
size greater than 128 bytes and an unaligned source address. This bug
is known to be the cause of random user process memory corruptions
while perf is running with the callgraph option (ie, perf record -g).
This occurs because perf uses copy_from_user() to read user stacks,
and may fault when it follows a stack frame pointer off to an
invalid page. Validation checks on the stack address just obscure
the underlying problem.
Signed-off-by: Rob Gardner <rob.gardner@oracle.com>
Signed-off-by: Dave Aldridge <david.j.aldridge@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-23 06:24:49 +00:00
|
|
|
EX_LD_FP(LOAD(ldd, %g1 + 0x00, %f0))
|
|
|
|
|
1: EX_LD_FP(LOAD(ldd, %g1 + 0x08, %f2))
|
2012-09-27 04:11:01 +00:00
|
|
|
subcc %o4, 0x40, %o4
|
sparc64: fix FP corruption in user copy functions
Short story: Exception handlers used by some copy_to_user() and
copy_from_user() functions do not diligently clean up floating point
register usage, and this can result in a user process seeing invalid
values in floating point registers. This sometimes makes the process
fail.
Long story: Several cpu-specific (NG4, NG2, U1, U3) memcpy functions
use floating point registers and VIS alignaddr/faligndata to
accelerate data copying when source and dest addresses don't align
well. Linux uses a lazy scheme for saving floating point registers; It
is not done upon entering the kernel since it's a very expensive
operation. Rather, it is done only when needed. If the kernel ends up
not using FP regs during the course of some trap or system call, then
it can return to user space without saving or restoring them.
The various memcpy functions begin their FP code with VISEntry (or a
variation thereof), which saves the FP regs. They conclude their FP
code with VISExit (or a variation) which essentially marks the FP regs
"clean", ie, they contain no unsaved values. fprs.FPRS_FEF is turned
off so that a lazy restore will be triggered when/if the user process
accesses floating point regs again.
The bug is that the user copy variants of memcpy, copy_from_user() and
copy_to_user(), employ an exception handling mechanism to detect faults
when accessing user space addresses, and when this handler is invoked,
an immediate return from the function is forced, and VISExit is not
executed, thus leaving the fprs register in an indeterminate state,
but often with fprs.FPRS_FEF set and one or more dirty bits. This
results in a return to user space with invalid values in the FP regs,
and since fprs.FPRS_FEF is on, no lazy restore occurs.
This bug affects copy_to_user() and copy_from_user() for NG4, NG2,
U3, and U1. All are fixed by using a new exception handler for those
loads and stores that are done during the time between VISEnter and
VISExit.
n.b. In NG4memcpy, the problematic code can be triggered by a copy
size greater than 128 bytes and an unaligned source address. This bug
is known to be the cause of random user process memory corruptions
while perf is running with the callgraph option (ie, perf record -g).
This occurs because perf uses copy_from_user() to read user stacks,
and may fault when it follows a stack frame pointer off to an
invalid page. Validation checks on the stack address just obscure
the underlying problem.
Signed-off-by: Rob Gardner <rob.gardner@oracle.com>
Signed-off-by: Dave Aldridge <david.j.aldridge@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-23 06:24:49 +00:00
|
|
|
EX_LD_FP(LOAD(ldd, %g1 + 0x10, %f4))
|
|
|
|
|
EX_LD_FP(LOAD(ldd, %g1 + 0x18, %f6))
|
|
|
|
|
EX_LD_FP(LOAD(ldd, %g1 + 0x20, %f8))
|
|
|
|
|
EX_LD_FP(LOAD(ldd, %g1 + 0x28, %f10))
|
|
|
|
|
EX_LD_FP(LOAD(ldd, %g1 + 0x30, %f12))
|
|
|
|
|
EX_LD_FP(LOAD(ldd, %g1 + 0x38, %f14))
|
2012-09-27 04:11:01 +00:00
|
|
|
faligndata %f0, %f2, %f16
|
sparc64: fix FP corruption in user copy functions
Short story: Exception handlers used by some copy_to_user() and
copy_from_user() functions do not diligently clean up floating point
register usage, and this can result in a user process seeing invalid
values in floating point registers. This sometimes makes the process
fail.
Long story: Several cpu-specific (NG4, NG2, U1, U3) memcpy functions
use floating point registers and VIS alignaddr/faligndata to
accelerate data copying when source and dest addresses don't align
well. Linux uses a lazy scheme for saving floating point registers; It
is not done upon entering the kernel since it's a very expensive
operation. Rather, it is done only when needed. If the kernel ends up
not using FP regs during the course of some trap or system call, then
it can return to user space without saving or restoring them.
The various memcpy functions begin their FP code with VISEntry (or a
variation thereof), which saves the FP regs. They conclude their FP
code with VISExit (or a variation) which essentially marks the FP regs
"clean", ie, they contain no unsaved values. fprs.FPRS_FEF is turned
off so that a lazy restore will be triggered when/if the user process
accesses floating point regs again.
The bug is that the user copy variants of memcpy, copy_from_user() and
copy_to_user(), employ an exception handling mechanism to detect faults
when accessing user space addresses, and when this handler is invoked,
an immediate return from the function is forced, and VISExit is not
executed, thus leaving the fprs register in an indeterminate state,
but often with fprs.FPRS_FEF set and one or more dirty bits. This
results in a return to user space with invalid values in the FP regs,
and since fprs.FPRS_FEF is on, no lazy restore occurs.
This bug affects copy_to_user() and copy_from_user() for NG4, NG2,
U3, and U1. All are fixed by using a new exception handler for those
loads and stores that are done during the time between VISEnter and
VISExit.
n.b. In NG4memcpy, the problematic code can be triggered by a copy
size greater than 128 bytes and an unaligned source address. This bug
is known to be the cause of random user process memory corruptions
while perf is running with the callgraph option (ie, perf record -g).
This occurs because perf uses copy_from_user() to read user stacks,
and may fault when it follows a stack frame pointer off to an
invalid page. Validation checks on the stack address just obscure
the underlying problem.
Signed-off-by: Rob Gardner <rob.gardner@oracle.com>
Signed-off-by: Dave Aldridge <david.j.aldridge@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-23 06:24:49 +00:00
|
|
|
EX_LD_FP(LOAD(ldd, %g1 + 0x40, %f0))
|
2012-09-27 04:11:01 +00:00
|
|
|
faligndata %f2, %f4, %f18
|
|
|
|
|
add %g1, 0x40, %g1
|
|
|
|
|
faligndata %f4, %f6, %f20
|
|
|
|
|
faligndata %f6, %f8, %f22
|
|
|
|
|
faligndata %f8, %f10, %f24
|
|
|
|
|
faligndata %f10, %f12, %f26
|
|
|
|
|
faligndata %f12, %f14, %f28
|
|
|
|
|
faligndata %f14, %f0, %f30
|
sparc64: fix FP corruption in user copy functions
Short story: Exception handlers used by some copy_to_user() and
copy_from_user() functions do not diligently clean up floating point
register usage, and this can result in a user process seeing invalid
values in floating point registers. This sometimes makes the process
fail.
Long story: Several cpu-specific (NG4, NG2, U1, U3) memcpy functions
use floating point registers and VIS alignaddr/faligndata to
accelerate data copying when source and dest addresses don't align
well. Linux uses a lazy scheme for saving floating point registers; It
is not done upon entering the kernel since it's a very expensive
operation. Rather, it is done only when needed. If the kernel ends up
not using FP regs during the course of some trap or system call, then
it can return to user space without saving or restoring them.
The various memcpy functions begin their FP code with VISEntry (or a
variation thereof), which saves the FP regs. They conclude their FP
code with VISExit (or a variation) which essentially marks the FP regs
"clean", ie, they contain no unsaved values. fprs.FPRS_FEF is turned
off so that a lazy restore will be triggered when/if the user process
accesses floating point regs again.
The bug is that the user copy variants of memcpy, copy_from_user() and
copy_to_user(), employ an exception handling mechanism to detect faults
when accessing user space addresses, and when this handler is invoked,
an immediate return from the function is forced, and VISExit is not
executed, thus leaving the fprs register in an indeterminate state,
but often with fprs.FPRS_FEF set and one or more dirty bits. This
results in a return to user space with invalid values in the FP regs,
and since fprs.FPRS_FEF is on, no lazy restore occurs.
This bug affects copy_to_user() and copy_from_user() for NG4, NG2,
U3, and U1. All are fixed by using a new exception handler for those
loads and stores that are done during the time between VISEnter and
VISExit.
n.b. In NG4memcpy, the problematic code can be triggered by a copy
size greater than 128 bytes and an unaligned source address. This bug
is known to be the cause of random user process memory corruptions
while perf is running with the callgraph option (ie, perf record -g).
This occurs because perf uses copy_from_user() to read user stacks,
and may fault when it follows a stack frame pointer off to an
invalid page. Validation checks on the stack address just obscure
the underlying problem.
Signed-off-by: Rob Gardner <rob.gardner@oracle.com>
Signed-off-by: Dave Aldridge <david.j.aldridge@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-23 06:24:49 +00:00
|
|
|
EX_ST_FP(STORE(std, %f16, %o0 + 0x00))
|
|
|
|
|
EX_ST_FP(STORE(std, %f18, %o0 + 0x08))
|
|
|
|
|
EX_ST_FP(STORE(std, %f20, %o0 + 0x10))
|
|
|
|
|
EX_ST_FP(STORE(std, %f22, %o0 + 0x18))
|
|
|
|
|
EX_ST_FP(STORE(std, %f24, %o0 + 0x20))
|
|
|
|
|
EX_ST_FP(STORE(std, %f26, %o0 + 0x28))
|
|
|
|
|
EX_ST_FP(STORE(std, %f28, %o0 + 0x30))
|
|
|
|
|
EX_ST_FP(STORE(std, %f30, %o0 + 0x38))
|
2012-09-27 04:11:01 +00:00
|
|
|
add %o0, 0x40, %o0
|
|
|
|
|
bne,pt %icc, 1b
|
|
|
|
|
LOAD(prefetch, %g1 + 0x200, #n_reads_strong)
|
2015-08-07 02:13:25 +00:00
|
|
|
#ifdef NON_USER_COPY
|
|
|
|
|
VISExitHalfFast
|
|
|
|
|
#else
|
2012-09-27 04:11:01 +00:00
|
|
|
VISExitHalf
|
2015-08-07 02:13:25 +00:00
|
|
|
#endif
|
2012-09-27 04:11:01 +00:00
|
|
|
brz,pn %o2, .Lexit
|
|
|
|
|
cmp %o2, 19
|
|
|
|
|
ble,pn %icc, .Lsmall_unaligned
|
|
|
|
|
nop
|
|
|
|
|
ba,a,pt %icc, .Lmedium_unaligned
|
|
|
|
|
|
sparc64: Fix FPU register corruption with AES crypto offload.
The AES loops in arch/sparc/crypto/aes_glue.c use a scheme where the
key material is preloaded into the FPU registers, and then we loop
over and over doing the crypt operation, reusing those pre-cooked key
registers.
There are intervening blkcipher*() calls between the crypt operation
calls. And those might perform memcpy() and thus also try to use the
FPU.
The sparc64 kernel FPU usage mechanism is designed to allow such
recursive uses, but with a catch.
There has to be a trap between the two FPU using threads of control.
The mechanism works by, when the FPU is already in use by the kernel,
allocating a slot for FPU saving at trap time. Then if, within the
trap handler, we try to use the FPU registers, the pre-trap FPU
register state is saved into the slot. Then at trap return time we
notice this and restore the pre-trap FPU state.
Over the long term there are various more involved ways we can make
this work, but for a quick fix let's take advantage of the fact that
the situation where this happens is very limited.
All sparc64 chips that support the crypto instructiosn also are using
the Niagara4 memcpy routine, and that routine only uses the FPU for
large copies where we can't get the source aligned properly to a
multiple of 8 bytes.
We look to see if the FPU is already in use in this context, and if so
we use the non-large copy path which only uses integer registers.
Furthermore, we also limit this special logic to when we are doing
kernel copy, rather than a user copy.
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-10-15 02:37:58 +00:00
|
|
|
#ifdef NON_USER_COPY
|
|
|
|
|
.Lmedium_vis_entry_fail:
|
|
|
|
|
or %o0, %o1, %g2
|
|
|
|
|
#endif
|
2012-09-27 04:11:01 +00:00
|
|
|
.Lmedium:
|
|
|
|
|
LOAD(prefetch, %o1 + 0x40, #n_reads_strong)
|
|
|
|
|
andcc %g2, 0x7, %g0
|
|
|
|
|
bne,pn %icc, .Lmedium_unaligned
|
|
|
|
|
nop
|
|
|
|
|
.Lmedium_noprefetch:
|
|
|
|
|
andncc %o2, 0x20 - 1, %o5
|
|
|
|
|
be,pn %icc, 2f
|
|
|
|
|
sub %o2, %o5, %o2
|
|
|
|
|
1: EX_LD(LOAD(ldx, %o1 + 0x00, %g1))
|
|
|
|
|
EX_LD(LOAD(ldx, %o1 + 0x08, %g2))
|
|
|
|
|
EX_LD(LOAD(ldx, %o1 + 0x10, GLOBAL_SPARE))
|
|
|
|
|
EX_LD(LOAD(ldx, %o1 + 0x18, %o4))
|
|
|
|
|
add %o1, 0x20, %o1
|
|
|
|
|
subcc %o5, 0x20, %o5
|
|
|
|
|
EX_ST(STORE(stx, %g1, %o0 + 0x00))
|
|
|
|
|
EX_ST(STORE(stx, %g2, %o0 + 0x08))
|
|
|
|
|
EX_ST(STORE(stx, GLOBAL_SPARE, %o0 + 0x10))
|
|
|
|
|
EX_ST(STORE(stx, %o4, %o0 + 0x18))
|
|
|
|
|
bne,pt %icc, 1b
|
|
|
|
|
add %o0, 0x20, %o0
|
|
|
|
|
2: andcc %o2, 0x18, %o5
|
|
|
|
|
be,pt %icc, 3f
|
|
|
|
|
sub %o2, %o5, %o2
|
|
|
|
|
1: EX_LD(LOAD(ldx, %o1 + 0x00, %g1))
|
|
|
|
|
add %o1, 0x08, %o1
|
|
|
|
|
add %o0, 0x08, %o0
|
|
|
|
|
subcc %o5, 0x08, %o5
|
|
|
|
|
bne,pt %icc, 1b
|
|
|
|
|
EX_ST(STORE(stx, %g1, %o0 - 0x08))
|
|
|
|
|
3: brz,pt %o2, .Lexit
|
|
|
|
|
cmp %o2, 0x04
|
|
|
|
|
bl,pn %icc, .Ltiny
|
|
|
|
|
nop
|
|
|
|
|
EX_LD(LOAD(lduw, %o1 + 0x00, %g1))
|
|
|
|
|
add %o1, 0x04, %o1
|
|
|
|
|
add %o0, 0x04, %o0
|
|
|
|
|
subcc %o2, 0x04, %o2
|
|
|
|
|
bne,pn %icc, .Ltiny
|
|
|
|
|
EX_ST(STORE(stw, %g1, %o0 - 0x04))
|
|
|
|
|
ba,a,pt %icc, .Lexit
|
|
|
|
|
.Lmedium_unaligned:
|
|
|
|
|
/* First get dest 8 byte aligned. */
|
|
|
|
|
sub %g0, %o0, %g1
|
|
|
|
|
and %g1, 0x7, %g1
|
|
|
|
|
brz,pt %g1, 2f
|
|
|
|
|
sub %o2, %g1, %o2
|
2012-09-28 20:08:22 +00:00
|
|
|
|
2012-09-27 04:11:01 +00:00
|
|
|
1: EX_LD(LOAD(ldub, %o1 + 0x00, %g2))
|
|
|
|
|
add %o1, 1, %o1
|
|
|
|
|
subcc %g1, 1, %g1
|
|
|
|
|
add %o0, 1, %o0
|
|
|
|
|
bne,pt %icc, 1b
|
|
|
|
|
EX_ST(STORE(stb, %g2, %o0 - 0x01))
|
|
|
|
|
2:
|
|
|
|
|
and %o1, 0x7, %g1
|
|
|
|
|
brz,pn %g1, .Lmedium_noprefetch
|
|
|
|
|
sll %g1, 3, %g1
|
|
|
|
|
mov 64, %g2
|
|
|
|
|
sub %g2, %g1, %g2
|
|
|
|
|
andn %o1, 0x7, %o1
|
|
|
|
|
EX_LD(LOAD(ldx, %o1 + 0x00, %o4))
|
|
|
|
|
sllx %o4, %g1, %o4
|
|
|
|
|
andn %o2, 0x08 - 1, %o5
|
|
|
|
|
sub %o2, %o5, %o2
|
|
|
|
|
1: EX_LD(LOAD(ldx, %o1 + 0x08, %g3))
|
|
|
|
|
add %o1, 0x08, %o1
|
|
|
|
|
subcc %o5, 0x08, %o5
|
|
|
|
|
srlx %g3, %g2, GLOBAL_SPARE
|
|
|
|
|
or GLOBAL_SPARE, %o4, GLOBAL_SPARE
|
|
|
|
|
EX_ST(STORE(stx, GLOBAL_SPARE, %o0 + 0x00))
|
|
|
|
|
add %o0, 0x08, %o0
|
|
|
|
|
bne,pt %icc, 1b
|
|
|
|
|
sllx %g3, %g1, %o4
|
|
|
|
|
srl %g1, 3, %g1
|
|
|
|
|
add %o1, %g1, %o1
|
|
|
|
|
brz,pn %o2, .Lexit
|
|
|
|
|
nop
|
|
|
|
|
ba,pt %icc, .Lsmall_unaligned
|
|
|
|
|
|
|
|
|
|
.Ltiny:
|
|
|
|
|
EX_LD(LOAD(ldub, %o1 + 0x00, %g1))
|
|
|
|
|
subcc %o2, 1, %o2
|
|
|
|
|
be,pn %icc, .Lexit
|
|
|
|
|
EX_ST(STORE(stb, %g1, %o0 + 0x00))
|
|
|
|
|
EX_LD(LOAD(ldub, %o1 + 0x01, %g1))
|
|
|
|
|
subcc %o2, 1, %o2
|
|
|
|
|
be,pn %icc, .Lexit
|
|
|
|
|
EX_ST(STORE(stb, %g1, %o0 + 0x01))
|
|
|
|
|
EX_LD(LOAD(ldub, %o1 + 0x02, %g1))
|
|
|
|
|
ba,pt %icc, .Lexit
|
|
|
|
|
EX_ST(STORE(stb, %g1, %o0 + 0x02))
|
|
|
|
|
|
|
|
|
|
.Lsmall:
|
|
|
|
|
andcc %g2, 0x3, %g0
|
|
|
|
|
bne,pn %icc, .Lsmall_unaligned
|
|
|
|
|
andn %o2, 0x4 - 1, %o5
|
|
|
|
|
sub %o2, %o5, %o2
|
|
|
|
|
1:
|
|
|
|
|
EX_LD(LOAD(lduw, %o1 + 0x00, %g1))
|
|
|
|
|
add %o1, 0x04, %o1
|
|
|
|
|
subcc %o5, 0x04, %o5
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add %o0, 0x04, %o0
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bne,pt %icc, 1b
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EX_ST(STORE(stw, %g1, %o0 - 0x04))
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brz,pt %o2, .Lexit
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nop
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ba,a,pt %icc, .Ltiny
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.Lsmall_unaligned:
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1: EX_LD(LOAD(ldub, %o1 + 0x00, %g1))
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add %o1, 1, %o1
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add %o0, 1, %o0
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subcc %o2, 1, %o2
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bne,pt %icc, 1b
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EX_ST(STORE(stb, %g1, %o0 - 0x01))
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ba,a,pt %icc, .Lexit
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.size FUNC_NAME, .-FUNC_NAME
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