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Merge branch 'for-next/extable' into for-next/core

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* for-next/extable:
  arm64: extable: cleanup redundant extable type EX_TYPE_FIXUP
  arm64: extable: move _cond_extable to _cond_uaccess_extable
  arm64: extable: make uaaccess helper use extable type EX_TYPE_UACCESS_ERR_ZERO
  arm64: asm-extable: add asm uacess helpers
  arm64: asm-extable: move data fields
  arm64: extable: add new extable type EX_TYPE_KACCESS_ERR_ZERO support
This commit is contained in:
Will Deacon 2022-07-25 10:56:16 +01:00
commit ee8b00a956
5 changed files with 111 additions and 88 deletions
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79
arch/arm64/include/asm/asm-extable.h
View File

@ -2,12 +2,27 @@
#ifndef __ASM_ASM_EXTABLE_H
#define __ASM_ASM_EXTABLE_H
#include <linux/bits.h>
#include <asm/gpr-num.h>
#define EX_TYPE_NONE 0
#define EX_TYPE_FIXUP 1
#define EX_TYPE_BPF 2
#define EX_TYPE_UACCESS_ERR_ZERO 3
#define EX_TYPE_BPF 1
#define EX_TYPE_UACCESS_ERR_ZERO 2
#define EX_TYPE_KACCESS_ERR_ZERO 3
#define EX_TYPE_LOAD_UNALIGNED_ZEROPAD 4
/* Data fields for EX_TYPE_UACCESS_ERR_ZERO */
#define EX_DATA_REG_ERR_SHIFT 0
#define EX_DATA_REG_ERR GENMASK(4, 0)
#define EX_DATA_REG_ZERO_SHIFT 5
#define EX_DATA_REG_ZERO GENMASK(9, 5)
/* Data fields for EX_TYPE_LOAD_UNALIGNED_ZEROPAD */
#define EX_DATA_REG_DATA_SHIFT 0
#define EX_DATA_REG_DATA GENMASK(4, 0)
#define EX_DATA_REG_ADDR_SHIFT 5
#define EX_DATA_REG_ADDR GENMASK(9, 5)
#ifdef __ASSEMBLY__
#define __ASM_EXTABLE_RAW(insn, fixup, type, data) \
@ -19,31 +34,45 @@
.short (data); \
.popsection;
#define EX_DATA_REG(reg, gpr) \
(.L__gpr_num_##gpr << EX_DATA_REG_##reg##_SHIFT)
#define _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, zero) \
__ASM_EXTABLE_RAW(insn, fixup, \
EX_TYPE_UACCESS_ERR_ZERO, \
( \
EX_DATA_REG(ERR, err) | \
EX_DATA_REG(ZERO, zero) \
))
#define _ASM_EXTABLE_UACCESS_ERR(insn, fixup, err) \
_ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, wzr)
#define _ASM_EXTABLE_UACCESS(insn, fixup) \
_ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, wzr, wzr)
/*
* Create an exception table entry for `insn`, which will branch to `fixup`
* Create an exception table entry for uaccess `insn`, which will branch to `fixup`
* when an unhandled fault is taken.
*/
.macro _asm_extable, insn, fixup
__ASM_EXTABLE_RAW(\insn, \fixup, EX_TYPE_FIXUP, 0)
.macro _asm_extable_uaccess, insn, fixup
_ASM_EXTABLE_UACCESS(\insn, \fixup)
.endm
/*
* Create an exception table entry for `insn` if `fixup` is provided. Otherwise
* do nothing.
*/
.macro _cond_extable, insn, fixup
.ifnc \fixup,
_asm_extable \insn, \fixup
.macro _cond_uaccess_extable, insn, fixup
.ifnc \fixup,
_asm_extable_uaccess \insn, \fixup
.endif
.endm
#else /* __ASSEMBLY__ */
#include <linux/bits.h>
#include <linux/stringify.h>
#include <asm/gpr-num.h>
#define __ASM_EXTABLE_RAW(insn, fixup, type, data) \
".pushsection __ex_table, \"a\"\n" \
".align 2\n" \
@ -53,14 +82,6 @@
".short (" data ")\n" \
".popsection\n"
#define _ASM_EXTABLE(insn, fixup) \
__ASM_EXTABLE_RAW(#insn, #fixup, __stringify(EX_TYPE_FIXUP), "0")
#define EX_DATA_REG_ERR_SHIFT 0
#define EX_DATA_REG_ERR GENMASK(4, 0)
#define EX_DATA_REG_ZERO_SHIFT 5
#define EX_DATA_REG_ZERO GENMASK(9, 5)
#define EX_DATA_REG(reg, gpr) \
"((.L__gpr_num_" #gpr ") << " __stringify(EX_DATA_REG_##reg##_SHIFT) ")"
@ -73,13 +94,23 @@
EX_DATA_REG(ZERO, zero) \
")")
#define _ASM_EXTABLE_KACCESS_ERR_ZERO(insn, fixup, err, zero) \
__DEFINE_ASM_GPR_NUMS \
__ASM_EXTABLE_RAW(#insn, #fixup, \
__stringify(EX_TYPE_KACCESS_ERR_ZERO), \
"(" \
EX_DATA_REG(ERR, err) " | " \
EX_DATA_REG(ZERO, zero) \
")")
#define _ASM_EXTABLE_UACCESS_ERR(insn, fixup, err) \
_ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, wzr)
#define EX_DATA_REG_DATA_SHIFT 0
#define EX_DATA_REG_DATA GENMASK(4, 0)
#define EX_DATA_REG_ADDR_SHIFT 5
#define EX_DATA_REG_ADDR GENMASK(9, 5)
#define _ASM_EXTABLE_UACCESS(insn, fixup) \
_ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, wzr, wzr)
#define _ASM_EXTABLE_KACCESS_ERR(insn, fixup, err) \
_ASM_EXTABLE_KACCESS_ERR_ZERO(insn, fixup, err, wzr)
#define _ASM_EXTABLE_LOAD_UNALIGNED_ZEROPAD(insn, fixup, data, addr) \
__DEFINE_ASM_GPR_NUMS \

12
arch/arm64/include/asm/asm-uaccess.h
View File

@ -61,7 +61,7 @@ alternative_else_nop_endif
#define USER(l, x...) \
9999: x; \
_asm_extable 9999b, l
_asm_extable_uaccess 9999b, l
/*
* Generate the assembly for LDTR/STTR with exception table entries.
@ -73,8 +73,8 @@ alternative_else_nop_endif
8889: ldtr \reg2, [\addr, #8];
add \addr, \addr, \post_inc;
_asm_extable 8888b,\l;
_asm_extable 8889b,\l;
_asm_extable_uaccess 8888b, \l;
_asm_extable_uaccess 8889b, \l;
.endm
.macro user_stp l, reg1, reg2, addr, post_inc
@ -82,14 +82,14 @@ alternative_else_nop_endif
8889: sttr \reg2, [\addr, #8];
add \addr, \addr, \post_inc;
_asm_extable 8888b,\l;
_asm_extable 8889b,\l;
_asm_extable_uaccess 8888b,\l;
_asm_extable_uaccess 8889b,\l;
.endm
.macro user_ldst l, inst, reg, addr, post_inc
8888: \inst \reg, [\addr];
add \addr, \addr, \post_inc;
_asm_extable 8888b,\l;
_asm_extable_uaccess 8888b, \l;
.endm
#endif

4
arch/arm64/include/asm/assembler.h
View File

@ -423,7 +423,7 @@ alternative_endif
b.lo .Ldcache_op\@
dsb \domain
_cond_extable .Ldcache_op\@, \fixup
_cond_uaccess_extable .Ldcache_op\@, \fixup
.endm
/*
@ -462,7 +462,7 @@ alternative_endif
dsb ish
isb
_cond_extable .Licache_op\@, \fixup
_cond_uaccess_extable .Licache_op\@, \fixup
.endm
/*

94
arch/arm64/include/asm/uaccess.h
View File

@ -232,34 +232,34 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr)
* The "__xxx_error" versions set the third argument to -EFAULT if an error
* occurs, and leave it unchanged on success.
*/
#define __get_mem_asm(load, reg, x, addr, err) \
#define __get_mem_asm(load, reg, x, addr, err, type) \
asm volatile( \
"1: " load " " reg "1, [%2]\n" \
"2:\n" \
_ASM_EXTABLE_UACCESS_ERR_ZERO(1b, 2b, %w0, %w1) \
_ASM_EXTABLE_##type##ACCESS_ERR_ZERO(1b, 2b, %w0, %w1) \
: "+r" (err), "=&r" (x) \
: "r" (addr))
#define __raw_get_mem(ldr, x, ptr, err) \
do { \
unsigned long __gu_val; \
switch (sizeof(*(ptr))) { \
case 1: \
__get_mem_asm(ldr "b", "%w", __gu_val, (ptr), (err)); \
break; \
case 2: \
__get_mem_asm(ldr "h", "%w", __gu_val, (ptr), (err)); \
break; \
case 4: \
__get_mem_asm(ldr, "%w", __gu_val, (ptr), (err)); \
break; \
case 8: \
__get_mem_asm(ldr, "%x", __gu_val, (ptr), (err)); \
break; \
default: \
BUILD_BUG(); \
} \
(x) = (__force __typeof__(*(ptr)))__gu_val; \
#define __raw_get_mem(ldr, x, ptr, err, type) \
do { \
unsigned long __gu_val; \
switch (sizeof(*(ptr))) { \
case 1: \
__get_mem_asm(ldr "b", "%w", __gu_val, (ptr), (err), type); \
break; \
case 2: \
__get_mem_asm(ldr "h", "%w", __gu_val, (ptr), (err), type); \
break; \
case 4: \
__get_mem_asm(ldr, "%w", __gu_val, (ptr), (err), type); \
break; \
case 8: \
__get_mem_asm(ldr, "%x", __gu_val, (ptr), (err), type); \
break; \
default: \
BUILD_BUG(); \
} \
(x) = (__force __typeof__(*(ptr)))__gu_val; \
} while (0)
/*
@ -274,7 +274,7 @@ do { \
__chk_user_ptr(ptr); \
\
uaccess_ttbr0_enable(); \
__raw_get_mem("ldtr", __rgu_val, __rgu_ptr, err); \
__raw_get_mem("ldtr", __rgu_val, __rgu_ptr, err, U); \
uaccess_ttbr0_disable(); \
\
(x) = __rgu_val; \
@ -314,40 +314,40 @@ do { \
\
__uaccess_enable_tco_async(); \
__raw_get_mem("ldr", *((type *)(__gkn_dst)), \
(__force type *)(__gkn_src), __gkn_err); \
(__force type *)(__gkn_src), __gkn_err, K); \
__uaccess_disable_tco_async(); \
\
if (unlikely(__gkn_err)) \
goto err_label; \
} while (0)
#define __put_mem_asm(store, reg, x, addr, err) \
#define __put_mem_asm(store, reg, x, addr, err, type) \
asm volatile( \
"1: " store " " reg "1, [%2]\n" \
"2:\n" \
_ASM_EXTABLE_UACCESS_ERR(1b, 2b, %w0) \
_ASM_EXTABLE_##type##ACCESS_ERR(1b, 2b, %w0) \
: "+r" (err) \
: "r" (x), "r" (addr))
#define __raw_put_mem(str, x, ptr, err) \
do { \
__typeof__(*(ptr)) __pu_val = (x); \
switch (sizeof(*(ptr))) { \
case 1: \
__put_mem_asm(str "b", "%w", __pu_val, (ptr), (err)); \
break; \
case 2: \
__put_mem_asm(str "h", "%w", __pu_val, (ptr), (err)); \
break; \
case 4: \
__put_mem_asm(str, "%w", __pu_val, (ptr), (err)); \
break; \
case 8: \
__put_mem_asm(str, "%x", __pu_val, (ptr), (err)); \
break; \
default: \
BUILD_BUG(); \
} \
#define __raw_put_mem(str, x, ptr, err, type) \
do { \
__typeof__(*(ptr)) __pu_val = (x); \
switch (sizeof(*(ptr))) { \
case 1: \
__put_mem_asm(str "b", "%w", __pu_val, (ptr), (err), type); \
break; \
case 2: \
__put_mem_asm(str "h", "%w", __pu_val, (ptr), (err), type); \
break; \
case 4: \
__put_mem_asm(str, "%w", __pu_val, (ptr), (err), type); \
break; \
case 8: \
__put_mem_asm(str, "%x", __pu_val, (ptr), (err), type); \
break; \
default: \
BUILD_BUG(); \
} \
} while (0)
/*
@ -362,7 +362,7 @@ do { \
__chk_user_ptr(__rpu_ptr); \
\
uaccess_ttbr0_enable(); \
__raw_put_mem("sttr", __rpu_val, __rpu_ptr, err); \
__raw_put_mem("sttr", __rpu_val, __rpu_ptr, err, U); \
uaccess_ttbr0_disable(); \
} while (0)
@ -400,7 +400,7 @@ do { \
\
__uaccess_enable_tco_async(); \
__raw_put_mem("str", *((type *)(__pkn_src)), \
(__force type *)(__pkn_dst), __pkn_err); \
(__force type *)(__pkn_dst), __pkn_err, K); \
__uaccess_disable_tco_async(); \
\
if (unlikely(__pkn_err)) \

10
arch/arm64/mm/extable.c
View File

@ -16,13 +16,6 @@ get_ex_fixup(const struct exception_table_entry *ex)
return ((unsigned long)&ex->fixup + ex->fixup);
}
static bool ex_handler_fixup(const struct exception_table_entry *ex,
struct pt_regs *regs)
{
regs->pc = get_ex_fixup(ex);
return true;
}
static bool ex_handler_uaccess_err_zero(const struct exception_table_entry *ex,
struct pt_regs *regs)
{
@ -72,11 +65,10 @@ bool fixup_exception(struct pt_regs *regs)
return false;
switch (ex->type) {
case EX_TYPE_FIXUP:
return ex_handler_fixup(ex, regs);
case EX_TYPE_BPF:
return ex_handler_bpf(ex, regs);
case EX_TYPE_UACCESS_ERR_ZERO:
case EX_TYPE_KACCESS_ERR_ZERO:
return ex_handler_uaccess_err_zero(ex, regs);
case EX_TYPE_LOAD_UNALIGNED_ZEROPAD:
return ex_handler_load_unaligned_zeropad(ex, regs);