abc71bf0a7
LLVM's integrated assembler doesn't support the LOCAL directive, which we're using when generating our uaccess fixup tables. Luckily the table fragment is small enough that there's only one internal symbol, so using a relative symbol reference doesn't really complicate anything. Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
127 lines
2.3 KiB
ArmAsm
127 lines
2.3 KiB
ArmAsm
#include <linux/linkage.h>
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#include <asm-generic/export.h>
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#include <asm/asm.h>
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#include <asm/csr.h>
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.macro fixup op reg addr lbl
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100:
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\op \reg, \addr
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.section __ex_table,"a"
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.balign RISCV_SZPTR
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RISCV_PTR 100b, \lbl
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.previous
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.endm
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ENTRY(__asm_copy_to_user)
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ENTRY(__asm_copy_from_user)
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/* Enable access to user memory */
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li t6, SR_SUM
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csrs CSR_STATUS, t6
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add a3, a1, a2
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/* Use word-oriented copy only if low-order bits match */
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andi t0, a0, SZREG-1
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andi t1, a1, SZREG-1
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bne t0, t1, 2f
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addi t0, a1, SZREG-1
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andi t1, a3, ~(SZREG-1)
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andi t0, t0, ~(SZREG-1)
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/*
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* a3: terminal address of source region
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* t0: lowest XLEN-aligned address in source
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* t1: highest XLEN-aligned address in source
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*/
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bgeu t0, t1, 2f
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bltu a1, t0, 4f
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1:
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fixup REG_L, t2, (a1), 10f
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fixup REG_S, t2, (a0), 10f
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addi a1, a1, SZREG
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addi a0, a0, SZREG
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bltu a1, t1, 1b
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2:
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bltu a1, a3, 5f
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3:
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/* Disable access to user memory */
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csrc CSR_STATUS, t6
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li a0, 0
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ret
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4: /* Edge case: unalignment */
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fixup lbu, t2, (a1), 10f
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fixup sb, t2, (a0), 10f
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addi a1, a1, 1
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addi a0, a0, 1
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bltu a1, t0, 4b
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j 1b
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5: /* Edge case: remainder */
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fixup lbu, t2, (a1), 10f
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fixup sb, t2, (a0), 10f
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addi a1, a1, 1
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addi a0, a0, 1
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bltu a1, a3, 5b
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j 3b
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ENDPROC(__asm_copy_to_user)
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ENDPROC(__asm_copy_from_user)
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EXPORT_SYMBOL(__asm_copy_to_user)
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EXPORT_SYMBOL(__asm_copy_from_user)
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ENTRY(__clear_user)
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/* Enable access to user memory */
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li t6, SR_SUM
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csrs CSR_STATUS, t6
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add a3, a0, a1
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addi t0, a0, SZREG-1
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andi t1, a3, ~(SZREG-1)
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andi t0, t0, ~(SZREG-1)
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/*
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* a3: terminal address of target region
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* t0: lowest doubleword-aligned address in target region
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* t1: highest doubleword-aligned address in target region
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*/
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bgeu t0, t1, 2f
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bltu a0, t0, 4f
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1:
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fixup REG_S, zero, (a0), 11f
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addi a0, a0, SZREG
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bltu a0, t1, 1b
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2:
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bltu a0, a3, 5f
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3:
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/* Disable access to user memory */
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csrc CSR_STATUS, t6
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li a0, 0
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ret
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4: /* Edge case: unalignment */
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fixup sb, zero, (a0), 11f
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addi a0, a0, 1
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bltu a0, t0, 4b
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j 1b
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5: /* Edge case: remainder */
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fixup sb, zero, (a0), 11f
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addi a0, a0, 1
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bltu a0, a3, 5b
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j 3b
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ENDPROC(__clear_user)
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EXPORT_SYMBOL(__clear_user)
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.section .fixup,"ax"
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.balign 4
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/* Fixup code for __copy_user(10) and __clear_user(11) */
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10:
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/* Disable access to user memory */
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csrs CSR_STATUS, t6
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mv a0, a2
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ret
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11:
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csrs CSR_STATUS, t6
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mv a0, a1
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ret
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.previous
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