On Tue, Jul 15, 2025 at 10:57:35PM +0000, Sami Tolvanen wrote: > From: Mark Rutland <mark.rutland@xxxxxxx> > > Currently x86 and riscv open-code 4 instances of the same logic to > define a u32 variable with the KCFI typeid of a given function. > > Replace the duplicate logic with a common macro. > > Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx> > Co-developed-by: Maxwell Bland <mbland@xxxxxxxxxxxx> > Signed-off-by: Maxwell Bland <mbland@xxxxxxxxxxxx> > Co-developed-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx> > Signed-off-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx> > Tested-by: Dao Huang <huangdao1@xxxxxxxx> > --- > arch/riscv/kernel/cfi.c | 35 +++-------------------------------- > arch/x86/kernel/alternative.c | 31 +++---------------------------- > include/linux/cfi_types.h | 23 +++++++++++++++++++++++ > 3 files changed, 29 insertions(+), 60 deletions(-) [...] > diff --git a/include/linux/cfi_types.h b/include/linux/cfi_types.h > index 6b8713675765..e5567c0fd0b3 100644 > --- a/include/linux/cfi_types.h > +++ b/include/linux/cfi_types.h > @@ -41,5 +41,28 @@ > SYM_TYPED_START(name, SYM_L_GLOBAL, SYM_A_ALIGN) > #endif > > +#else /* __ASSEMBLY__ */ > + > +#ifdef CONFIG_CFI_CLANG > +#define DEFINE_CFI_TYPE(name, func) \ > + /* \ > + * Force a reference to the function so the compiler generates \ > + * __kcfi_typeid_<func>. \ > + */ \ > + __ADDRESSABLE(func); \ > + /* u32 name __ro_after_init = __kcfi_typeid_<func> */ \ > + extern u32 name; \ > + asm ( \ > + " .pushsection .data..ro_after_init,\"aw\",@progbits \n" \ > + " .type " #name ",@object \n" \ > + " .globl " #name " \n" \ > + " .p2align 2, 0x0 \n" \ > + #name ": \n" \ > + " .4byte __kcfi_typeid_" #func " \n" \ > + " .size " #name ", 4 \n" \ > + " .popsection \n" \ > + ); > +#endif This looks good to me. I was initially a bit worried about the portability of the '.4byte' directive, but it seems that cfi_types.h is already using that for the __CFI_TYPE() macro so I'm assuming it's not an issue. In which case: Acked-by: Will Deacon <will@xxxxxxxxxx> Thanks for cleaning it up. Will
