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linux-stable/arch/x86/entry/calling.h
Uros Bizjak eb3621798b x86/entry/64: Do not include inst.h in calling.h 
inst.h was included in calling.h solely to instantiate the RDPID macro.
The usage of RDPID was removed in

  6a3ea3e68b ("x86/entry/64: Do not use RDPID in paranoid entry to accomodate KVM")

so remove the include.

Fixes: 6a3ea3e68b ("x86/entry/64: Do not use RDPID in paranoid entry to accomodate KVM")
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200827171735.93825-1-ubizjak@gmail.com
2020-09-04 10:59:21 +02:00

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/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/jump_label.h>
#include <asm/unwind_hints.h>
#include <asm/cpufeatures.h>
#include <asm/page_types.h>
#include <asm/percpu.h>
#include <asm/asm-offsets.h>
#include <asm/processor-flags.h>
/*
x86 function call convention, 64-bit:
-------------------------------------
arguments | callee-saved | extra caller-saved | return
[callee-clobbered] | | [callee-clobbered] |
---------------------------------------------------------------------------
rdi rsi rdx rcx r8-9 | rbx rbp [*] r12-15 | r10-11 | rax, rdx [**]
( rsp is obviously invariant across normal function calls. (gcc can 'merge'
functions when it sees tail-call optimization possibilities) rflags is
clobbered. Leftover arguments are passed over the stack frame.)
[*] In the frame-pointers case rbp is fixed to the stack frame.
[**] for struct return values wider than 64 bits the return convention is a
bit more complex: up to 128 bits width we return small structures
straight in rax, rdx. For structures larger than that (3 words or
larger) the caller puts a pointer to an on-stack return struct
[allocated in the caller's stack frame] into the first argument - i.e.
into rdi. All other arguments shift up by one in this case.
Fortunately this case is rare in the kernel.
For 32-bit we have the following conventions - kernel is built with
-mregparm=3 and -freg-struct-return:
x86 function calling convention, 32-bit:
----------------------------------------
arguments | callee-saved | extra caller-saved | return
[callee-clobbered] | | [callee-clobbered] |
-------------------------------------------------------------------------
eax edx ecx | ebx edi esi ebp [*] | <none> | eax, edx [**]
( here too esp is obviously invariant across normal function calls. eflags
is clobbered. Leftover arguments are passed over the stack frame. )
[*] In the frame-pointers case ebp is fixed to the stack frame.
[**] We build with -freg-struct-return, which on 32-bit means similar
semantics as on 64-bit: edx can be used for a second return value
(i.e. covering integer and structure sizes up to 64 bits) - after that
it gets more complex and more expensive: 3-word or larger struct returns
get done in the caller's frame and the pointer to the return struct goes
into regparm0, i.e. eax - the other arguments shift up and the
function's register parameters degenerate to regparm=2 in essence.
*/
#ifdef CONFIG_X86_64
/*
* 64-bit system call stack frame layout defines and helpers,
* for assembly code:
*/
/* The layout forms the "struct pt_regs" on the stack: */
/*
* C ABI says these regs are callee-preserved. They aren't saved on kernel entry
* unless syscall needs a complete, fully filled "struct pt_regs".
*/
#define R15 0*8
#define R14 1*8
#define R13 2*8
#define R12 3*8
#define RBP 4*8
#define RBX 5*8
/* These regs are callee-clobbered. Always saved on kernel entry. */
#define R11 6*8
#define R10 7*8
#define R9 8*8
#define R8 9*8
#define RAX 10*8
#define RCX 11*8
#define RDX 12*8
#define RSI 13*8
#define RDI 14*8
/*
* On syscall entry, this is syscall#. On CPU exception, this is error code.
* On hw interrupt, it's IRQ number:
*/
#define ORIG_RAX 15*8
/* Return frame for iretq */
#define RIP 16*8
#define CS 17*8
#define EFLAGS 18*8
#define RSP 19*8
#define SS 20*8
#define SIZEOF_PTREGS 21*8
.macro PUSH_AND_CLEAR_REGS rdx=%rdx rax=%rax save_ret=0
.if \save_ret
pushq %rsi /* pt_regs->si */
movq 8(%rsp), %rsi /* temporarily store the return address in %rsi */
movq %rdi, 8(%rsp) /* pt_regs->di (overwriting original return address) */
.else
pushq %rdi /* pt_regs->di */
pushq %rsi /* pt_regs->si */
.endif
pushq \rdx /* pt_regs->dx */
pushq %rcx /* pt_regs->cx */
pushq \rax /* pt_regs->ax */
pushq %r8 /* pt_regs->r8 */
pushq %r9 /* pt_regs->r9 */
pushq %r10 /* pt_regs->r10 */
pushq %r11 /* pt_regs->r11 */
pushq %rbx /* pt_regs->rbx */
pushq %rbp /* pt_regs->rbp */
pushq %r12 /* pt_regs->r12 */
pushq %r13 /* pt_regs->r13 */
pushq %r14 /* pt_regs->r14 */
pushq %r15 /* pt_regs->r15 */
UNWIND_HINT_REGS
.if \save_ret
pushq %rsi /* return address on top of stack */
.endif
/*
* Sanitize registers of values that a speculation attack might
* otherwise want to exploit. The lower registers are likely clobbered
* well before they could be put to use in a speculative execution
* gadget.
*/
xorl %edx, %edx /* nospec dx */
xorl %ecx, %ecx /* nospec cx */
xorl %r8d, %r8d /* nospec r8 */
xorl %r9d, %r9d /* nospec r9 */
xorl %r10d, %r10d /* nospec r10 */
xorl %r11d, %r11d /* nospec r11 */
xorl %ebx, %ebx /* nospec rbx */
xorl %ebp, %ebp /* nospec rbp */
xorl %r12d, %r12d /* nospec r12 */
xorl %r13d, %r13d /* nospec r13 */
xorl %r14d, %r14d /* nospec r14 */
xorl %r15d, %r15d /* nospec r15 */
.endm
.macro POP_REGS pop_rdi=1 skip_r11rcx=0
popq %r15
popq %r14
popq %r13
popq %r12
popq %rbp
popq %rbx
.if \skip_r11rcx
popq %rsi
.else
popq %r11
.endif
popq %r10
popq %r9
popq %r8
popq %rax
.if \skip_r11rcx
popq %rsi
.else
popq %rcx
.endif
popq %rdx
popq %rsi
.if \pop_rdi
popq %rdi
.endif
.endm
#ifdef CONFIG_PAGE_TABLE_ISOLATION
/*
* PAGE_TABLE_ISOLATION PGDs are 8k. Flip bit 12 to switch between the two
* halves:
*/
#define PTI_USER_PGTABLE_BIT PAGE_SHIFT
#define PTI_USER_PGTABLE_MASK (1 << PTI_USER_PGTABLE_BIT)
#define PTI_USER_PCID_BIT X86_CR3_PTI_PCID_USER_BIT
#define PTI_USER_PCID_MASK (1 << PTI_USER_PCID_BIT)
#define PTI_USER_PGTABLE_AND_PCID_MASK (PTI_USER_PCID_MASK | PTI_USER_PGTABLE_MASK)
.macro SET_NOFLUSH_BIT reg:req
bts $X86_CR3_PCID_NOFLUSH_BIT, \reg
.endm
.macro ADJUST_KERNEL_CR3 reg:req
ALTERNATIVE "", "SET_NOFLUSH_BIT \reg", X86_FEATURE_PCID
/* Clear PCID and "PAGE_TABLE_ISOLATION bit", point CR3 at kernel pagetables: */
andq $(~PTI_USER_PGTABLE_AND_PCID_MASK), \reg
.endm
.macro SWITCH_TO_KERNEL_CR3 scratch_reg:req
ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_PTI
mov %cr3, \scratch_reg
ADJUST_KERNEL_CR3 \scratch_reg
mov \scratch_reg, %cr3
.Lend_\@:
.endm
#define THIS_CPU_user_pcid_flush_mask \
PER_CPU_VAR(cpu_tlbstate) + TLB_STATE_user_pcid_flush_mask
.macro SWITCH_TO_USER_CR3_NOSTACK scratch_reg:req scratch_reg2:req
ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_PTI
mov %cr3, \scratch_reg
ALTERNATIVE "jmp .Lwrcr3_\@", "", X86_FEATURE_PCID
/*
* Test if the ASID needs a flush.
*/
movq \scratch_reg, \scratch_reg2
andq $(0x7FF), \scratch_reg /* mask ASID */
bt \scratch_reg, THIS_CPU_user_pcid_flush_mask
jnc .Lnoflush_\@
/* Flush needed, clear the bit */
btr \scratch_reg, THIS_CPU_user_pcid_flush_mask
movq \scratch_reg2, \scratch_reg
jmp .Lwrcr3_pcid_\@
.Lnoflush_\@:
movq \scratch_reg2, \scratch_reg
SET_NOFLUSH_BIT \scratch_reg
.Lwrcr3_pcid_\@:
/* Flip the ASID to the user version */
orq $(PTI_USER_PCID_MASK), \scratch_reg
.Lwrcr3_\@:
/* Flip the PGD to the user version */
orq $(PTI_USER_PGTABLE_MASK), \scratch_reg
mov \scratch_reg, %cr3
.Lend_\@:
.endm
.macro SWITCH_TO_USER_CR3_STACK scratch_reg:req
pushq %rax
SWITCH_TO_USER_CR3_NOSTACK scratch_reg=\scratch_reg scratch_reg2=%rax
popq %rax
.endm
.macro SAVE_AND_SWITCH_TO_KERNEL_CR3 scratch_reg:req save_reg:req
ALTERNATIVE "jmp .Ldone_\@", "", X86_FEATURE_PTI
movq %cr3, \scratch_reg
movq \scratch_reg, \save_reg
/*
* Test the user pagetable bit. If set, then the user page tables
* are active. If clear CR3 already has the kernel page table
* active.
*/
bt $PTI_USER_PGTABLE_BIT, \scratch_reg
jnc .Ldone_\@
ADJUST_KERNEL_CR3 \scratch_reg
movq \scratch_reg, %cr3
.Ldone_\@:
.endm
.macro RESTORE_CR3 scratch_reg:req save_reg:req
ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_PTI
ALTERNATIVE "jmp .Lwrcr3_\@", "", X86_FEATURE_PCID
/*
* KERNEL pages can always resume with NOFLUSH as we do
* explicit flushes.
*/
bt $PTI_USER_PGTABLE_BIT, \save_reg
jnc .Lnoflush_\@
/*
* Check if there's a pending flush for the user ASID we're
* about to set.
*/
movq \save_reg, \scratch_reg
andq $(0x7FF), \scratch_reg
bt \scratch_reg, THIS_CPU_user_pcid_flush_mask
jnc .Lnoflush_\@
btr \scratch_reg, THIS_CPU_user_pcid_flush_mask
jmp .Lwrcr3_\@
.Lnoflush_\@:
SET_NOFLUSH_BIT \save_reg
.Lwrcr3_\@:
/*
* The CR3 write could be avoided when not changing its value,
* but would require a CR3 read *and* a scratch register.
*/
movq \save_reg, %cr3
.Lend_\@:
.endm
#else /* CONFIG_PAGE_TABLE_ISOLATION=n: */
.macro SWITCH_TO_KERNEL_CR3 scratch_reg:req
.endm
.macro SWITCH_TO_USER_CR3_NOSTACK scratch_reg:req scratch_reg2:req
.endm
.macro SWITCH_TO_USER_CR3_STACK scratch_reg:req
.endm
.macro SAVE_AND_SWITCH_TO_KERNEL_CR3 scratch_reg:req save_reg:req
.endm
.macro RESTORE_CR3 scratch_reg:req save_reg:req
.endm
#endif
/*
* Mitigate Spectre v1 for conditional swapgs code paths.
*
* FENCE_SWAPGS_USER_ENTRY is used in the user entry swapgs code path, to
* prevent a speculative swapgs when coming from kernel space.
*
* FENCE_SWAPGS_KERNEL_ENTRY is used in the kernel entry non-swapgs code path,
* to prevent the swapgs from getting speculatively skipped when coming from
* user space.
*/
.macro FENCE_SWAPGS_USER_ENTRY
ALTERNATIVE "", "lfence", X86_FEATURE_FENCE_SWAPGS_USER
.endm
.macro FENCE_SWAPGS_KERNEL_ENTRY
ALTERNATIVE "", "lfence", X86_FEATURE_FENCE_SWAPGS_KERNEL
.endm
.macro STACKLEAK_ERASE_NOCLOBBER
#ifdef CONFIG_GCC_PLUGIN_STACKLEAK
PUSH_AND_CLEAR_REGS
call stackleak_erase
POP_REGS
#endif
.endm
.macro SAVE_AND_SET_GSBASE scratch_reg:req save_reg:req
rdgsbase \save_reg
GET_PERCPU_BASE \scratch_reg
wrgsbase \scratch_reg
.endm
#else /* CONFIG_X86_64 */
# undef UNWIND_HINT_IRET_REGS
# define UNWIND_HINT_IRET_REGS
#endif /* !CONFIG_X86_64 */
.macro STACKLEAK_ERASE
#ifdef CONFIG_GCC_PLUGIN_STACKLEAK
call stackleak_erase
#endif
.endm
#ifdef CONFIG_SMP
/*
* CPU/node NR is loaded from the limit (size) field of a special segment
* descriptor entry in GDT.
*/
.macro LOAD_CPU_AND_NODE_SEG_LIMIT reg:req
movq $__CPUNODE_SEG, \reg
lsl \reg, \reg
.endm
/*
* Fetch the per-CPU GSBASE value for this processor and put it in @reg.
* We normally use %gs for accessing per-CPU data, but we are setting up
* %gs here and obviously can not use %gs itself to access per-CPU data.
*
* Do not use RDPID, because KVM loads guest's TSC_AUX on vm-entry and
* may not restore the host's value until the CPU returns to userspace.
* Thus the kernel would consume a guest's TSC_AUX if an NMI arrives
* while running KVM's run loop.
*/
.macro GET_PERCPU_BASE reg:req
LOAD_CPU_AND_NODE_SEG_LIMIT \reg
andq $VDSO_CPUNODE_MASK, \reg
movq __per_cpu_offset(, \reg, 8), \reg
.endm
#else
.macro GET_PERCPU_BASE reg:req
movq pcpu_unit_offsets(%rip), \reg
.endm
#endif /* CONFIG_SMP */
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