| Message ID | 20191122022406.590141-3-pasha.tatashin@soleen.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Use C inlines for uaccess | expand |
Hi Pavel, On Thu, Nov 21, 2019 at 09:24:05PM -0500, Pavel Tatashin wrote: > Replace the uaccess_ttbr0_disable/uaccess_ttbr0_enable via > inline variants, and remove asm macros. A commit message should provide rationale, rather than just a description of the patch. Something like: | We currently duplicate the logic to enable/disable uaccess via TTBR0, | with C functions and assembly macros. This is a maintenenace burden | and is liable to lead to subtle bugs, so let's get rid of the assembly | macros, and always use the C functions. This requires refactoring | some assembly functions to have a C wrapper. [...] > +static inline int invalidate_icache_range(unsigned long start, > + unsigned long end) > +{ > + int rv; > +#if ARM64_HAS_CACHE_DIC > + rv = arch_invalidate_icache_range(start, end); > +#else > + uaccess_ttbr0_enable(); > + rv = arch_invalidate_icache_range(start, end); > + uaccess_ttbr0_disable(); > +#endif > + return rv; > +} This ifdeffery is not the same as an alternative_if, and even if it were the ARM64_HAS_CACHE_DIC behaviour is not the same as the existing assembly. This should be: static inline int invalidate_icache_range(unsigned long start, unsigned long end) { int ret; if (cpus_have_const_cap(ARM64_HAS_CACHE_DIC)) { isb(); return 0; } uaccess_ttbr0_enable(); ret = arch_invalidate_icache_range(start, end); uaccess_ttbr0_disable(); return ret; } The 'arch_' prefix should probably be 'asm_' (or have an '_asm' suffix), since this is entirely local to the arch code, and even then should only be called from the C wrappers. Thanks, Mark.
Hi Mark, Thank you for reviewing this work. > A commit message should provide rationale, rather than just a > description of the patch. Something like: > > | We currently duplicate the logic to enable/disable uaccess via TTBR0, > | with C functions and assembly macros. This is a maintenenace burden > | and is liable to lead to subtle bugs, so let's get rid of the assembly > | macros, and always use the C functions. This requires refactoring > | some assembly functions to have a C wrapper. Thank you for suggestion, I will fix my commit log. > > [...] > > > +static inline int invalidate_icache_range(unsigned long start, > > + unsigned long end) > > +{ > > + int rv; > > +#if ARM64_HAS_CACHE_DIC > > + rv = arch_invalidate_icache_range(start, end); > > +#else > > + uaccess_ttbr0_enable(); > > + rv = arch_invalidate_icache_range(start, end); > > + uaccess_ttbr0_disable(); > > +#endif > > + return rv; > > +} > > This ifdeffery is not the same as an alternative_if, and even if it were > the ARM64_HAS_CACHE_DIC behaviour is not the same as the existing > assembly. > > This should be: > > static inline int invalidate_icache_range(unsigned long start, > unsigned long end) > { > int ret; > > if (cpus_have_const_cap(ARM64_HAS_CACHE_DIC)) { > isb(); > return 0; > } > > uaccess_ttbr0_enable(); > ret = arch_invalidate_icache_range(start, end); > uaccess_ttbr0_disable(); > > return ret; > } I will fix it, thanks. > > The 'arch_' prefix should probably be 'asm_' (or have an '_asm' suffix), > since this is entirely local to the arch code, and even then should only > be called from the C wrappers. Sure, I can change it to asm_*, I was using arch_* to be consistent with __arch_copy_from_user() and friends. Thank you, Pasha
On Wed, Nov 27, 2019 at 10:10:07AM -0500, Pavel Tatashin wrote: > Hi Mark, > > Thank you for reviewing this work. > > The 'arch_' prefix should probably be 'asm_' (or have an '_asm' suffix), > > since this is entirely local to the arch code, and even then should only > > be called from the C wrappers. > > Sure, I can change it to asm_*, I was using arch_* to be consistent > with __arch_copy_from_user() and friends. FWIW, that naming was from before the common uaccess code took on the raw_* anming for the arch functions, and I was expecting that the arch_* functions would end up being called from core code. For now it's probably too churny to change that existing case. Thanks, Mark.
diff --git a/arch/arm64/include/asm/asm-uaccess.h b/arch/arm64/include/asm/asm-uaccess.h index 35e6145e1402..8f763e5b41b1 100644 --- a/arch/arm64/include/asm/asm-uaccess.h +++ b/arch/arm64/include/asm/asm-uaccess.h @@ -34,27 +34,5 @@ msr ttbr0_el1, \tmp1 // set the non-PAN TTBR0_EL1 isb .endm - - .macro uaccess_ttbr0_disable, tmp1, tmp2 -alternative_if_not ARM64_HAS_PAN - save_and_disable_irq \tmp2 // avoid preemption - __uaccess_ttbr0_disable \tmp1 - restore_irq \tmp2 -alternative_else_nop_endif - .endm - - .macro uaccess_ttbr0_enable, tmp1, tmp2, tmp3 -alternative_if_not ARM64_HAS_PAN - save_and_disable_irq \tmp3 // avoid preemption - __uaccess_ttbr0_enable \tmp1, \tmp2 - restore_irq \tmp3 -alternative_else_nop_endif - .endm -#else - .macro uaccess_ttbr0_disable, tmp1, tmp2 - .endm - - .macro uaccess_ttbr0_enable, tmp1, tmp2, tmp3 - .endm #endif #endif diff --git a/arch/arm64/include/asm/cacheflush.h b/arch/arm64/include/asm/cacheflush.h index 665c78e0665a..cdd4a8eb8708 100644 --- a/arch/arm64/include/asm/cacheflush.h +++ b/arch/arm64/include/asm/cacheflush.h @@ -61,16 +61,48 @@ * - kaddr - page address * - size - region size */ -extern void __flush_icache_range(unsigned long start, unsigned long end); -extern int invalidate_icache_range(unsigned long start, unsigned long end); +extern void __arch_flush_icache_range(unsigned long start, unsigned long end); +extern long __arch_flush_cache_user_range(unsigned long start, + unsigned long end); +extern int arch_invalidate_icache_range(unsigned long start, + unsigned long end); + extern void __flush_dcache_area(void *addr, size_t len); extern void __inval_dcache_area(void *addr, size_t len); extern void __clean_dcache_area_poc(void *addr, size_t len); extern void __clean_dcache_area_pop(void *addr, size_t len); extern void __clean_dcache_area_pou(void *addr, size_t len); -extern long __flush_cache_user_range(unsigned long start, unsigned long end); extern void sync_icache_aliases(void *kaddr, unsigned long len); +static inline void __flush_icache_range(unsigned long start, unsigned long end) +{ + uaccess_ttbr0_enable(); + __arch_flush_icache_range(start, end); + uaccess_ttbr0_disable(); +} + +static inline void __flush_cache_user_range(unsigned long start, + unsigned long end) +{ + uaccess_ttbr0_enable(); + __arch_flush_cache_user_range(start, end); + uaccess_ttbr0_disable(); +} + +static inline int invalidate_icache_range(unsigned long start, + unsigned long end) +{ + int rv; +#if ARM64_HAS_CACHE_DIC + rv = arch_invalidate_icache_range(start, end); +#else + uaccess_ttbr0_enable(); + rv = arch_invalidate_icache_range(start, end); + uaccess_ttbr0_disable(); +#endif + return rv; +} + static inline void flush_icache_range(unsigned long start, unsigned long end) { __flush_icache_range(start, end); diff --git a/arch/arm64/mm/cache.S b/arch/arm64/mm/cache.S index db767b072601..408d317a47d2 100644 --- a/arch/arm64/mm/cache.S +++ b/arch/arm64/mm/cache.S @@ -15,7 +15,7 @@ #include <asm/asm-uaccess.h> /* - * flush_icache_range(start,end) + * __arch_flush_icache_range(start,end) * * Ensure that the I and D caches are coherent within specified region. * This is typically used when code has been written to a memory region, @@ -24,11 +24,11 @@ * - start - virtual start address of region * - end - virtual end address of region */ -ENTRY(__flush_icache_range) +ENTRY(__arch_flush_icache_range) /* FALLTHROUGH */ /* - * __flush_cache_user_range(start,end) + * __arch_flush_cache_user_range(start,end) * * Ensure that the I and D caches are coherent within specified region. * This is typically used when code has been written to a memory region, @@ -37,8 +37,7 @@ ENTRY(__flush_icache_range) * - start - virtual start address of region * - end - virtual end address of region */ -ENTRY(__flush_cache_user_range) - uaccess_ttbr0_enable x2, x3, x4 +ENTRY(__arch_flush_cache_user_range) alternative_if ARM64_HAS_CACHE_IDC dsb ishst b 7f @@ -60,14 +59,11 @@ alternative_if ARM64_HAS_CACHE_DIC alternative_else_nop_endif invalidate_icache_by_line x0, x1, x2, x3, 9f 8: mov x0, #0 -1: - uaccess_ttbr0_disable x1, x2 - ret -9: - mov x0, #-EFAULT +1: ret +9: mov x0, #-EFAULT b 1b -ENDPROC(__flush_icache_range) -ENDPROC(__flush_cache_user_range) +ENDPROC(__arch_flush_icache_range) +ENDPROC(__arch_flush_cache_user_range) /* * invalidate_icache_range(start,end) @@ -83,16 +79,10 @@ alternative_if ARM64_HAS_CACHE_DIC isb ret alternative_else_nop_endif - - uaccess_ttbr0_enable x2, x3, x4 - invalidate_icache_by_line x0, x1, x2, x3, 2f mov x0, xzr -1: - uaccess_ttbr0_disable x1, x2 - ret -2: - mov x0, #-EFAULT +1: ret +2: mov x0, #-EFAULT b 1b ENDPROC(invalidate_icache_range) diff --git a/arch/arm64/mm/flush.c b/arch/arm64/mm/flush.c index ac485163a4a7..66249fca2092 100644 --- a/arch/arm64/mm/flush.c +++ b/arch/arm64/mm/flush.c @@ -75,7 +75,7 @@ EXPORT_SYMBOL(flush_dcache_page); /* * Additional functions defined in assembly. */ -EXPORT_SYMBOL(__flush_icache_range); +EXPORT_SYMBOL(__arch_flush_icache_range); #ifdef CONFIG_ARCH_HAS_PMEM_API void arch_wb_cache_pmem(void *addr, size_t size)
Replace the uaccess_ttbr0_disable/uaccess_ttbr0_enable via inline variants, and remove asm macros. Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com> --- arch/arm64/include/asm/asm-uaccess.h | 22 ---------------- arch/arm64/include/asm/cacheflush.h | 38 +++++++++++++++++++++++++--- arch/arm64/mm/cache.S | 30 ++++++++-------------- arch/arm64/mm/flush.c | 2 +- 4 files changed, 46 insertions(+), 46 deletions(-)