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| author | Juergen Gross <jgross@suse.com> | 2024-11-29 16:15:54 +0100 |
|---|---|---|
| committer | Juergen Gross <jgross@suse.com> | 2024-12-13 09:28:32 +0100 |
| commit | 0ef8047b737d7480a5d4c46d956e97c190f13050 (patch) | |
| tree | 34ac003c882605b69761786af8e121a68d1e6e24 /include | |
| parent | dda014ba59331dee4f3b773a020e109932f4bd24 (diff) | |
| download | lwn-0ef8047b737d7480a5d4c46d956e97c190f13050.tar.gz lwn-0ef8047b737d7480a5d4c46d956e97c190f13050.zip | |
x86/static-call: provide a way to do very early static-call updates
Add static_call_update_early() for updating static-call targets in
very early boot.
This will be needed for support of Xen guest type specific hypercall
functions.
This is part of XSA-466 / CVE-2024-53241.
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Co-developed-by: Peter Zijlstra <peterz@infradead.org>
Co-developed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/compiler.h | 37 | ||||
| -rw-r--r-- | include/linux/static_call.h | 1 |
2 files changed, 27 insertions, 11 deletions
diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 469a64dd6495..240c632c5b95 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -216,28 +216,43 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, #endif /* __KERNEL__ */ +/** + * offset_to_ptr - convert a relative memory offset to an absolute pointer + * @off: the address of the 32-bit offset value + */ +static inline void *offset_to_ptr(const int *off) +{ + return (void *)((unsigned long)off + *off); +} + +#endif /* __ASSEMBLY__ */ + +#ifdef CONFIG_64BIT +#define ARCH_SEL(a,b) a +#else +#define ARCH_SEL(a,b) b +#endif + /* * Force the compiler to emit 'sym' as a symbol, so that we can reference * it from inline assembler. Necessary in case 'sym' could be inlined * otherwise, or eliminated entirely due to lack of references that are * visible to the compiler. */ -#define ___ADDRESSABLE(sym, __attrs) \ - static void * __used __attrs \ +#define ___ADDRESSABLE(sym, __attrs) \ + static void * __used __attrs \ __UNIQUE_ID(__PASTE(__addressable_,sym)) = (void *)(uintptr_t)&sym; + #define __ADDRESSABLE(sym) \ ___ADDRESSABLE(sym, __section(".discard.addressable")) -/** - * offset_to_ptr - convert a relative memory offset to an absolute pointer - * @off: the address of the 32-bit offset value - */ -static inline void *offset_to_ptr(const int *off) -{ - return (void *)((unsigned long)off + *off); -} +#define __ADDRESSABLE_ASM(sym) \ + .pushsection .discard.addressable,"aw"; \ + .align ARCH_SEL(8,4); \ + ARCH_SEL(.quad, .long) __stringify(sym); \ + .popsection; -#endif /* __ASSEMBLY__ */ +#define __ADDRESSABLE_ASM_STR(sym) __stringify(__ADDRESSABLE_ASM(sym)) #ifdef __CHECKER__ #define __BUILD_BUG_ON_ZERO_MSG(e, msg) (0) diff --git a/include/linux/static_call.h b/include/linux/static_call.h index 141e6b176a1b..785980af8972 100644 --- a/include/linux/static_call.h +++ b/include/linux/static_call.h @@ -138,6 +138,7 @@ #ifdef CONFIG_HAVE_STATIC_CALL #include <asm/static_call.h> +extern int static_call_initialized; /* * Either @site or @tramp can be NULL. */ |