On Mon, Mar 09, 2020 at 12:17:14PM +0000, Mark Rutland wrote: > On Sat, Mar 07, 2020 at 04:39:26PM +0700, Phong Tran wrote: > > follow the suggestion from > > https://github.com/KSPP/linux/issues/35 > > That says: > > | This should be implemented for all architectures > > ... so surely this should be in generic code, rahter than being > arm64-specific? > > Thanks, > Mark. > > > > > Signed-off-by: Phong Tran <tranmanphong@xxxxxxxxx> > > --- > > arch/arm64/Kconfig.debug | 3 ++- > > arch/arm64/include/asm/ptdump.h | 2 ++ > > arch/arm64/mm/dump.c | 1 + > > arch/arm64/mm/ptdump_debugfs.c | 18 ++++++++++++++++++ > > 4 files changed, 23 insertions(+), 1 deletion(-) > > > > diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug > > index 1c906d932d6b..be552fa351e2 100644 > > --- a/arch/arm64/Kconfig.debug > > +++ b/arch/arm64/Kconfig.debug > > @@ -48,7 +48,8 @@ config DEBUG_WX > > of other unfixed kernel bugs easier. > > > > There is no runtime or memory usage effect of this option > > - once the kernel has booted up - it's a one time check. > > + once the kernel has booted up - it's a one time check and > > + can be checked by echo "1" to "check_wx_pages" debugfs in runtime. > > > > If in doubt, say "Y". > > > > diff --git a/arch/arm64/include/asm/ptdump.h b/arch/arm64/include/asm/ptdump.h > > index 38187f74e089..b80d6b4fc508 100644 > > --- a/arch/arm64/include/asm/ptdump.h > > +++ b/arch/arm64/include/asm/ptdump.h > > @@ -24,9 +24,11 @@ struct ptdump_info { > > void ptdump_walk(struct seq_file *s, struct ptdump_info *info); > > #ifdef CONFIG_PTDUMP_DEBUGFS > > void ptdump_debugfs_register(struct ptdump_info *info, const char *name); > > +int ptdump_check_wx_init(void); > > #else > > static inline void ptdump_debugfs_register(struct ptdump_info *info, > > const char *name) { } > > +static inline int ptdump_check_wx_init(void) { return 0; } > > #endif > > void ptdump_check_wx(void); > > #endif /* CONFIG_PTDUMP_CORE */ > > diff --git a/arch/arm64/mm/dump.c b/arch/arm64/mm/dump.c > > index 860c00ec8bd3..60c99a047763 100644 > > --- a/arch/arm64/mm/dump.c > > +++ b/arch/arm64/mm/dump.c > > @@ -378,6 +378,7 @@ static int ptdump_init(void) > > #endif > > ptdump_initialize(); > > ptdump_debugfs_register(&kernel_ptdump_info, "kernel_page_tables"); > > + ptdump_check_wx_init(); > > return 0; > > } > > device_initcall(ptdump_init); > > diff --git a/arch/arm64/mm/ptdump_debugfs.c b/arch/arm64/mm/ptdump_debugfs.c > > index 1f2eae3e988b..73cddc12c3c2 100644 > > --- a/arch/arm64/mm/ptdump_debugfs.c > > +++ b/arch/arm64/mm/ptdump_debugfs.c > > @@ -16,3 +16,21 @@ void ptdump_debugfs_register(struct ptdump_info *info, const char *name) > > { > > debugfs_create_file(name, 0400, NULL, info, &ptdump_fops); > > } > > + > > +static int check_wx_debugfs_set(void *data, u64 val) > > +{ > > + if (val != 1ULL) > > + return -EINVAL; > > + > > + ptdump_check_wx(); > > + > > + return 0; > > +} > > + > > +DEFINE_SIMPLE_ATTRIBUTE(check_wx_fops, NULL, check_wx_debugfs_set, "%llu\n"); > > + > > +int ptdump_check_wx_init(void) > > +{ > > + return debugfs_create_file("check_wx_pages", 0200, NULL, > > + NULL, &check_wx_fops) ? 0 : -ENOMEM; Do not check the return value of this function, especially as it is returning a pointer, not an int! Just call the function and move on, you should not do anything different if it returns an error or not. thanks, greg k-h
