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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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47d632f9f8
Use direct load/store for the get_user/put_user. Previously, we would call out to a helper routine that would do the appropriate thing and then return, handling the possible exception internally. Now we inline the load or store, along with a "we succeeded" indication in a register; if the load or store faults, we write a "we failed" indication into the same register and then return to the following instruction. This is more efficient and gives us more compact code, as well as being more in line with what other architectures do. The special futex assembly source file for TILE-Gx also disappears in this change; we just use the same inlining idiom there as well, putting the appropriate atomic operations directly into futex_atomic_op_inuser() (and thus into the FUTEX_WAIT function). The underlying atomic copy_from_user, copy_to_user functions were renamed using the (cryptic) x86 convention as copy_from_user_ll and copy_to_user_ll. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
147 lines
4.6 KiB
ArmAsm
147 lines
4.6 KiB
ArmAsm
/*
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* Copyright 2011 Tilera Corporation. All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, version 2.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
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* NON INFRINGEMENT. See the GNU General Public License for
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* more details.
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*/
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#include <linux/linkage.h>
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#include <asm/errno.h>
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#include <asm/cache.h>
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#include <arch/chip.h>
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/* Access user memory, but use MMU to avoid propagating kernel exceptions. */
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/*
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* strnlen_user_asm takes the pointer in r0, and the length bound in r1.
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* It returns the length, including the terminating NUL, or zero on exception.
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* If length is greater than the bound, returns one plus the bound.
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*/
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STD_ENTRY(strnlen_user_asm)
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{ beqz r1, 2f; addi r3, r0, -1 } /* bias down to include NUL */
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1: { ld1u r4, r0; addi r1, r1, -1 }
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beqz r4, 2f
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{ bnezt r1, 1b; addi r0, r0, 1 }
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2: { sub r0, r0, r3; jrp lr }
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STD_ENDPROC(strnlen_user_asm)
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.pushsection .fixup,"ax"
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strnlen_user_fault:
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{ move r0, zero; jrp lr }
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ENDPROC(strnlen_user_fault)
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.section __ex_table,"a"
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.quad 1b, strnlen_user_fault
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.popsection
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/*
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* strncpy_from_user_asm takes the kernel target pointer in r0,
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* the userspace source pointer in r1, and the length bound (including
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* the trailing NUL) in r2. On success, it returns the string length
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* (not including the trailing NUL), or -EFAULT on failure.
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*/
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STD_ENTRY(strncpy_from_user_asm)
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{ beqz r2, 2f; move r3, r0 }
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1: { ld1u r4, r1; addi r1, r1, 1; addi r2, r2, -1 }
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{ st1 r0, r4; addi r0, r0, 1 }
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beqz r2, 2f
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bnezt r4, 1b
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addi r0, r0, -1 /* don't count the trailing NUL */
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2: { sub r0, r0, r3; jrp lr }
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STD_ENDPROC(strncpy_from_user_asm)
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.pushsection .fixup,"ax"
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strncpy_from_user_fault:
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{ movei r0, -EFAULT; jrp lr }
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ENDPROC(strncpy_from_user_fault)
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.section __ex_table,"a"
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.quad 1b, strncpy_from_user_fault
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.popsection
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/*
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* clear_user_asm takes the user target address in r0 and the
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* number of bytes to zero in r1.
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* It returns the number of uncopiable bytes (hopefully zero) in r0.
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* Note that we don't use a separate .fixup section here since we fall
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* through into the "fixup" code as the last straight-line bundle anyway.
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*/
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STD_ENTRY(clear_user_asm)
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{ beqz r1, 2f; or r2, r0, r1 }
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andi r2, r2, 7
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beqzt r2, .Lclear_aligned_user_asm
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1: { st1 r0, zero; addi r0, r0, 1; addi r1, r1, -1 }
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bnezt r1, 1b
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2: { move r0, r1; jrp lr }
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.pushsection __ex_table,"a"
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.quad 1b, 2b
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.popsection
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.Lclear_aligned_user_asm:
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1: { st r0, zero; addi r0, r0, 8; addi r1, r1, -8 }
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bnezt r1, 1b
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2: { move r0, r1; jrp lr }
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STD_ENDPROC(clear_user_asm)
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.pushsection __ex_table,"a"
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.quad 1b, 2b
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.popsection
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/*
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* flush_user_asm takes the user target address in r0 and the
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* number of bytes to flush in r1.
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* It returns the number of unflushable bytes (hopefully zero) in r0.
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*/
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STD_ENTRY(flush_user_asm)
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beqz r1, 2f
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{ movei r2, L2_CACHE_BYTES; add r1, r0, r1 }
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{ sub r2, zero, r2; addi r1, r1, L2_CACHE_BYTES-1 }
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{ and r0, r0, r2; and r1, r1, r2 }
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{ sub r1, r1, r0 }
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1: { flush r0; addi r1, r1, -CHIP_FLUSH_STRIDE() }
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{ addi r0, r0, CHIP_FLUSH_STRIDE(); bnezt r1, 1b }
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2: { move r0, r1; jrp lr }
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STD_ENDPROC(flush_user_asm)
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.pushsection __ex_table,"a"
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.quad 1b, 2b
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.popsection
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/*
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* inv_user_asm takes the user target address in r0 and the
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* number of bytes to invalidate in r1.
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* It returns the number of not inv'able bytes (hopefully zero) in r0.
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*/
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STD_ENTRY(inv_user_asm)
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beqz r1, 2f
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{ movei r2, L2_CACHE_BYTES; add r1, r0, r1 }
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{ sub r2, zero, r2; addi r1, r1, L2_CACHE_BYTES-1 }
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{ and r0, r0, r2; and r1, r1, r2 }
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{ sub r1, r1, r0 }
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1: { inv r0; addi r1, r1, -CHIP_INV_STRIDE() }
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{ addi r0, r0, CHIP_INV_STRIDE(); bnezt r1, 1b }
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2: { move r0, r1; jrp lr }
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STD_ENDPROC(inv_user_asm)
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.pushsection __ex_table,"a"
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.quad 1b, 2b
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.popsection
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/*
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* finv_user_asm takes the user target address in r0 and the
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* number of bytes to flush-invalidate in r1.
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* It returns the number of not finv'able bytes (hopefully zero) in r0.
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*/
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STD_ENTRY(finv_user_asm)
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beqz r1, 2f
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{ movei r2, L2_CACHE_BYTES; add r1, r0, r1 }
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{ sub r2, zero, r2; addi r1, r1, L2_CACHE_BYTES-1 }
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{ and r0, r0, r2; and r1, r1, r2 }
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{ sub r1, r1, r0 }
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1: { finv r0; addi r1, r1, -CHIP_FINV_STRIDE() }
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{ addi r0, r0, CHIP_FINV_STRIDE(); bnezt r1, 1b }
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2: { move r0, r1; jrp lr }
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STD_ENDPROC(finv_user_asm)
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.pushsection __ex_table,"a"
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.quad 1b, 2b
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.popsection
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