| Message ID | 20220420030418.3189040-7-tongtiangen@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: add machine check safe support | expand |
On Wed, Apr 20, 2022 at 03:04:17AM +0000, Tong Tiangen wrote: > Add {get, put}_user() to machine check safe. > > If get/put fail due to hardware memory error, only the relevant processes > are affected, so killing the user process and isolate the user page with > hardware memory errors is a more reasonable choice than kernel panic. > > Add new extable type EX_TYPE_UACCESS_MC_ERR_ZERO which can be used for > uaccess that can be recovered from hardware memory errors. The difference > from EX_TYPE_UACCESS_MC is that this type also sets additional two target > register which save error code and value needs to be set zero. Why does this need to be in any way distinct from the existing EX_TYPE_UACCESS_ERR_ZERO ? Other than the case where we currently (ab)use that for copy_{to,from}_kernel_nofault(), where do we *not* want to use EX_TYPE_UACCESS_ERR_ZERO and *not* recover from a memory error? Thanks, Mark. > > Signed-off-by: Tong Tiangen <tongtiangen@huawei.com> > --- > arch/arm64/include/asm/asm-extable.h | 14 ++++++++++++++ > arch/arm64/include/asm/uaccess.h | 4 ++-- > arch/arm64/mm/extable.c | 4 ++++ > 3 files changed, 20 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/include/asm/asm-extable.h b/arch/arm64/include/asm/asm-extable.h > index 75b2c00e9523..80410899a9ad 100644 > --- a/arch/arm64/include/asm/asm-extable.h > +++ b/arch/arm64/include/asm/asm-extable.h > @@ -13,6 +13,7 @@ > > /* _MC indicates that can fixup from machine check errors */ > #define EX_TYPE_UACCESS_MC 5 > +#define EX_TYPE_UACCESS_MC_ERR_ZERO 6 > > #ifdef __ASSEMBLY__ > > @@ -78,6 +79,15 @@ > #define EX_DATA_REG(reg, gpr) \ > "((.L__gpr_num_" #gpr ") << " __stringify(EX_DATA_REG_##reg##_SHIFT) ")" > > +#define _ASM_EXTABLE_UACCESS_MC_ERR_ZERO(insn, fixup, err, zero) \ > + __DEFINE_ASM_GPR_NUMS \ > + __ASM_EXTABLE_RAW(#insn, #fixup, \ > + __stringify(EX_TYPE_UACCESS_MC_ERR_ZERO), \ > + "(" \ > + EX_DATA_REG(ERR, err) " | " \ > + EX_DATA_REG(ZERO, zero) \ > + ")") > + > #define _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, zero) \ > __DEFINE_ASM_GPR_NUMS \ > __ASM_EXTABLE_RAW(#insn, #fixup, \ > @@ -90,6 +100,10 @@ > #define _ASM_EXTABLE_UACCESS_ERR(insn, fixup, err) \ > _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, wzr) > > + > +#define _ASM_EXTABLE_UACCESS_MC_ERR(insn, fixup, err) \ > + _ASM_EXTABLE_UACCESS_MC_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 > diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h > index e8dce0cc5eaa..e41b47df48b0 100644 > --- a/arch/arm64/include/asm/uaccess.h > +++ b/arch/arm64/include/asm/uaccess.h > @@ -236,7 +236,7 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr) > asm volatile( \ > "1: " load " " reg "1, [%2]\n" \ > "2:\n" \ > - _ASM_EXTABLE_UACCESS_ERR_ZERO(1b, 2b, %w0, %w1) \ > + _ASM_EXTABLE_UACCESS_MC_ERR_ZERO(1b, 2b, %w0, %w1) \ > : "+r" (err), "=&r" (x) \ > : "r" (addr)) > > @@ -325,7 +325,7 @@ do { \ > asm volatile( \ > "1: " store " " reg "1, [%2]\n" \ > "2:\n" \ > - _ASM_EXTABLE_UACCESS_ERR(1b, 2b, %w0) \ > + _ASM_EXTABLE_UACCESS_MC_ERR(1b, 2b, %w0) \ > : "+r" (err) \ > : "r" (x), "r" (addr)) > > diff --git a/arch/arm64/mm/extable.c b/arch/arm64/mm/extable.c > index 525876c3ebf4..1023ccdb2f89 100644 > --- a/arch/arm64/mm/extable.c > +++ b/arch/arm64/mm/extable.c > @@ -88,6 +88,7 @@ bool fixup_exception(struct pt_regs *regs) > case EX_TYPE_BPF: > return ex_handler_bpf(ex, regs); > case EX_TYPE_UACCESS_ERR_ZERO: > + case EX_TYPE_UACCESS_MC_ERR_ZERO: > return ex_handler_uaccess_err_zero(ex, regs); > case EX_TYPE_LOAD_UNALIGNED_ZEROPAD: > return ex_handler_load_unaligned_zeropad(ex, regs); > @@ -107,6 +108,9 @@ bool fixup_exception_mc(struct pt_regs *regs) > switch (ex->type) { > case EX_TYPE_UACCESS_MC: > return ex_handler_uaccess_type(ex, regs, FIXUP_TYPE_MC); > + case EX_TYPE_UACCESS_MC_ERR_ZERO: > + return ex_handler_uaccess_err_zero(ex, regs); > + > } > > return false; > -- > 2.25.1 >
在 2022/5/13 23:39, Mark Rutland 写道: > On Wed, Apr 20, 2022 at 03:04:17AM +0000, Tong Tiangen wrote: >> Add {get, put}_user() to machine check safe. >> >> If get/put fail due to hardware memory error, only the relevant processes >> are affected, so killing the user process and isolate the user page with >> hardware memory errors is a more reasonable choice than kernel panic. >> >> Add new extable type EX_TYPE_UACCESS_MC_ERR_ZERO which can be used for >> uaccess that can be recovered from hardware memory errors. The difference >> from EX_TYPE_UACCESS_MC is that this type also sets additional two target >> register which save error code and value needs to be set zero. > > Why does this need to be in any way distinct from the existing > EX_TYPE_UACCESS_ERR_ZERO ? > > Other than the case where we currently (ab)use that for > copy_{to,from}_kernel_nofault(), where do we *not* want to use > EX_TYPE_UACCESS_ERR_ZERO and *not* recover from a memory error? > > Thanks, > Mark. There are some cases (futex/__user_cache_maint()/__user_swpX_asm()) using EX_TYPE_UACCESS_ERR_ZERO, for these cases, whether to restore is not yet determined, let's discuss in patch 3/7. Thanks, Tong. > >> >> Signed-off-by: Tong Tiangen <tongtiangen@huawei.com> >> --- >> arch/arm64/include/asm/asm-extable.h | 14 ++++++++++++++ >> arch/arm64/include/asm/uaccess.h | 4 ++-- >> arch/arm64/mm/extable.c | 4 ++++ >> 3 files changed, 20 insertions(+), 2 deletions(-) >> >> diff --git a/arch/arm64/include/asm/asm-extable.h b/arch/arm64/include/asm/asm-extable.h >> index 75b2c00e9523..80410899a9ad 100644 >> --- a/arch/arm64/include/asm/asm-extable.h >> +++ b/arch/arm64/include/asm/asm-extable.h >> @@ -13,6 +13,7 @@ >> >> /* _MC indicates that can fixup from machine check errors */ >> #define EX_TYPE_UACCESS_MC 5 >> +#define EX_TYPE_UACCESS_MC_ERR_ZERO 6 >> >> #ifdef __ASSEMBLY__ >> >> @@ -78,6 +79,15 @@ >> #define EX_DATA_REG(reg, gpr) \ >> "((.L__gpr_num_" #gpr ") << " __stringify(EX_DATA_REG_##reg##_SHIFT) ")" >> >> +#define _ASM_EXTABLE_UACCESS_MC_ERR_ZERO(insn, fixup, err, zero) \ >> + __DEFINE_ASM_GPR_NUMS \ >> + __ASM_EXTABLE_RAW(#insn, #fixup, \ >> + __stringify(EX_TYPE_UACCESS_MC_ERR_ZERO), \ >> + "(" \ >> + EX_DATA_REG(ERR, err) " | " \ >> + EX_DATA_REG(ZERO, zero) \ >> + ")") >> + >> #define _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, zero) \ >> __DEFINE_ASM_GPR_NUMS \ >> __ASM_EXTABLE_RAW(#insn, #fixup, \ >> @@ -90,6 +100,10 @@ >> #define _ASM_EXTABLE_UACCESS_ERR(insn, fixup, err) \ >> _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, wzr) >> >> + >> +#define _ASM_EXTABLE_UACCESS_MC_ERR(insn, fixup, err) \ >> + _ASM_EXTABLE_UACCESS_MC_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 >> diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h >> index e8dce0cc5eaa..e41b47df48b0 100644 >> --- a/arch/arm64/include/asm/uaccess.h >> +++ b/arch/arm64/include/asm/uaccess.h >> @@ -236,7 +236,7 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr) >> asm volatile( \ >> "1: " load " " reg "1, [%2]\n" \ >> "2:\n" \ >> - _ASM_EXTABLE_UACCESS_ERR_ZERO(1b, 2b, %w0, %w1) \ >> + _ASM_EXTABLE_UACCESS_MC_ERR_ZERO(1b, 2b, %w0, %w1) \ >> : "+r" (err), "=&r" (x) \ >> : "r" (addr)) >> >> @@ -325,7 +325,7 @@ do { \ >> asm volatile( \ >> "1: " store " " reg "1, [%2]\n" \ >> "2:\n" \ >> - _ASM_EXTABLE_UACCESS_ERR(1b, 2b, %w0) \ >> + _ASM_EXTABLE_UACCESS_MC_ERR(1b, 2b, %w0) \ >> : "+r" (err) \ >> : "r" (x), "r" (addr)) >> >> diff --git a/arch/arm64/mm/extable.c b/arch/arm64/mm/extable.c >> index 525876c3ebf4..1023ccdb2f89 100644 >> --- a/arch/arm64/mm/extable.c >> +++ b/arch/arm64/mm/extable.c >> @@ -88,6 +88,7 @@ bool fixup_exception(struct pt_regs *regs) >> case EX_TYPE_BPF: >> return ex_handler_bpf(ex, regs); >> case EX_TYPE_UACCESS_ERR_ZERO: >> + case EX_TYPE_UACCESS_MC_ERR_ZERO: >> return ex_handler_uaccess_err_zero(ex, regs); >> case EX_TYPE_LOAD_UNALIGNED_ZEROPAD: >> return ex_handler_load_unaligned_zeropad(ex, regs); >> @@ -107,6 +108,9 @@ bool fixup_exception_mc(struct pt_regs *regs) >> switch (ex->type) { >> case EX_TYPE_UACCESS_MC: >> return ex_handler_uaccess_type(ex, regs, FIXUP_TYPE_MC); >> + case EX_TYPE_UACCESS_MC_ERR_ZERO: >> + return ex_handler_uaccess_err_zero(ex, regs); >> + >> } >> >> return false; >> -- >> 2.25.1 >> > .
diff --git a/arch/arm64/include/asm/asm-extable.h b/arch/arm64/include/asm/asm-extable.h index 75b2c00e9523..80410899a9ad 100644 --- a/arch/arm64/include/asm/asm-extable.h +++ b/arch/arm64/include/asm/asm-extable.h @@ -13,6 +13,7 @@ /* _MC indicates that can fixup from machine check errors */ #define EX_TYPE_UACCESS_MC 5 +#define EX_TYPE_UACCESS_MC_ERR_ZERO 6 #ifdef __ASSEMBLY__ @@ -78,6 +79,15 @@ #define EX_DATA_REG(reg, gpr) \ "((.L__gpr_num_" #gpr ") << " __stringify(EX_DATA_REG_##reg##_SHIFT) ")" +#define _ASM_EXTABLE_UACCESS_MC_ERR_ZERO(insn, fixup, err, zero) \ + __DEFINE_ASM_GPR_NUMS \ + __ASM_EXTABLE_RAW(#insn, #fixup, \ + __stringify(EX_TYPE_UACCESS_MC_ERR_ZERO), \ + "(" \ + EX_DATA_REG(ERR, err) " | " \ + EX_DATA_REG(ZERO, zero) \ + ")") + #define _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, zero) \ __DEFINE_ASM_GPR_NUMS \ __ASM_EXTABLE_RAW(#insn, #fixup, \ @@ -90,6 +100,10 @@ #define _ASM_EXTABLE_UACCESS_ERR(insn, fixup, err) \ _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, wzr) + +#define _ASM_EXTABLE_UACCESS_MC_ERR(insn, fixup, err) \ + _ASM_EXTABLE_UACCESS_MC_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 diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index e8dce0cc5eaa..e41b47df48b0 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -236,7 +236,7 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr) asm volatile( \ "1: " load " " reg "1, [%2]\n" \ "2:\n" \ - _ASM_EXTABLE_UACCESS_ERR_ZERO(1b, 2b, %w0, %w1) \ + _ASM_EXTABLE_UACCESS_MC_ERR_ZERO(1b, 2b, %w0, %w1) \ : "+r" (err), "=&r" (x) \ : "r" (addr)) @@ -325,7 +325,7 @@ do { \ asm volatile( \ "1: " store " " reg "1, [%2]\n" \ "2:\n" \ - _ASM_EXTABLE_UACCESS_ERR(1b, 2b, %w0) \ + _ASM_EXTABLE_UACCESS_MC_ERR(1b, 2b, %w0) \ : "+r" (err) \ : "r" (x), "r" (addr)) diff --git a/arch/arm64/mm/extable.c b/arch/arm64/mm/extable.c index 525876c3ebf4..1023ccdb2f89 100644 --- a/arch/arm64/mm/extable.c +++ b/arch/arm64/mm/extable.c @@ -88,6 +88,7 @@ bool fixup_exception(struct pt_regs *regs) case EX_TYPE_BPF: return ex_handler_bpf(ex, regs); case EX_TYPE_UACCESS_ERR_ZERO: + case EX_TYPE_UACCESS_MC_ERR_ZERO: return ex_handler_uaccess_err_zero(ex, regs); case EX_TYPE_LOAD_UNALIGNED_ZEROPAD: return ex_handler_load_unaligned_zeropad(ex, regs); @@ -107,6 +108,9 @@ bool fixup_exception_mc(struct pt_regs *regs) switch (ex->type) { case EX_TYPE_UACCESS_MC: return ex_handler_uaccess_type(ex, regs, FIXUP_TYPE_MC); + case EX_TYPE_UACCESS_MC_ERR_ZERO: + return ex_handler_uaccess_err_zero(ex, regs); + } return false;
Add {get, put}_user() to machine check safe. If get/put fail due to hardware memory error, only the relevant processes are affected, so killing the user process and isolate the user page with hardware memory errors is a more reasonable choice than kernel panic. Add new extable type EX_TYPE_UACCESS_MC_ERR_ZERO which can be used for uaccess that can be recovered from hardware memory errors. The difference from EX_TYPE_UACCESS_MC is that this type also sets additional two target register which save error code and value needs to be set zero. Signed-off-by: Tong Tiangen <tongtiangen@huawei.com> --- arch/arm64/include/asm/asm-extable.h | 14 ++++++++++++++ arch/arm64/include/asm/uaccess.h | 4 ++-- arch/arm64/mm/extable.c | 4 ++++ 3 files changed, 20 insertions(+), 2 deletions(-)