On 18.12.24 09:37, Jiri Slaby wrote:
On 17. 12. 24, 18:08, Greg Kroah-Hartman wrote:6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Juergen Gross <jgross@xxxxxxxx> commit 0ef8047b737d7480a5d4c46d956e97c190f13050 upstream. 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@xxxxxxxxxx> Signed-off-by: Juergen Gross <jgross@xxxxxxxx> Co-developed-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Co-developed-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/x86/include/asm/static_call.h | 15 +++++++++++++++ arch/x86/include/asm/sync_core.h | 6 +++--- arch/x86/kernel/static_call.c | 9 +++++++++ include/linux/compiler.h | 37 ++++++++++++++++++++++++++----------- include/linux/static_call.h | 1 + kernel/static_call_inline.c | 2 +- 6 files changed, 55 insertions(+), 15 deletions(-) --- a/arch/x86/include/asm/static_call.h +++ b/arch/x86/include/asm/static_call.h @@ -65,4 +65,19 @@ extern bool __static_call_fixup(void *tramp, u8 op, void *dest); +extern void __static_call_update_early(void *tramp, void *func); + +#define static_call_update_early(name, _func) \ +({ \ + typeof(&STATIC_CALL_TRAMP(name)) __F = (_func); \ + if (static_call_initialized) { \ + __static_call_update(&STATIC_CALL_KEY(name), \ + STATIC_CALL_TRAMP_ADDR(name), __F);\ + } else { \ + WRITE_ONCE(STATIC_CALL_KEY(name).func, _func); \ + __static_call_update_early(STATIC_CALL_TRAMP_ADDR(name),\ + __F); \ + } \ +})...--- a/kernel/static_call_inline.c +++ b/kernel/static_call_inline.c @@ -15,7 +15,7 @@ extern struct static_call_site __start_s extern struct static_call_tramp_key __start_static_call_tramp_key[], __stop_static_call_tramp_key[]; -static int static_call_initialized; +int static_call_initialized;This breaks the build on i386:ld: arch/x86/xen/enlighten.o: in function `__xen_hypercall_setfunc':enlighten.c:(.noinstr.text+0x2a): undefined reference to `static_call_initialized' ld: enlighten.c:(.noinstr.text+0x62): undefined reference to `static_call_initialized'ld: arch/x86/kernel/static_call.o: in function `__static_call_update_early':static_call.c:(.noinstr.text+0x15): undefined reference to `static_call_initialized'kernel/static_call_inline.c containing this `static_call_initialized` is not built there as:HAVE_STATIC_CALL_INLINE=n -> HAVE_OBJTOOL=n -> X86_64=n This is broken in upstream too.
I've sent a fix already: https://lore.kernel.org/lkml/20241218080228.9742-1-jgross@xxxxxxxx/T/#u Juergen
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