6.12-stable review patch. If anyone has any objections, please let me know.
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From: Kai Huang kai.huang@intel.com
commit 0b3bc018e86afdc0cbfef61328c63d5c08f8b370 upstream.
Two 'static inline' TDX helper functions (sc_retry() and sc_retry_prerr()) take function pointer arguments which refer to assembly functions. Normally, the compiler inlines the TDX helper, realizes that the function pointer targets are completely static -- thus can be resolved at compile time -- and generates direct call instructions.
But, other times (like when CONFIG_CC_OPTIMIZE_FOR_SIZE=y), the compiler declines to inline the helpers and will instead generate indirect call instructions.
Indirect calls to assembly functions require special annotation (for various Control Flow Integrity mechanisms). But TDX assembly functions lack the special annotations and can only be called directly.
Annotate both the helpers as '__always_inline' to prod the compiler into maintaining the direct calls. There is no guarantee here, but Peter has volunteered to report the compiler bug if this assumption ever breaks[1].
Fixes: 1e66a7e27539 ("x86/virt/tdx: Handle SEAMCALL no entropy error in common code") Fixes: df01f5ae07dd ("x86/virt/tdx: Add SEAMCALL error printing for module initialization") Signed-off-by: Kai Huang kai.huang@intel.com Signed-off-by: Dave Hansen dave.hansen@linux.intel.com Cc: stable@vger.kernel.org Link: https://lore.kernel.org/lkml/20250605145914.GW39944@noisy.programming.kicks-... [1] Link: https://lore.kernel.org/all/20250606130737.30713-1-kai.huang%40intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/include/asm/tdx.h | 2 +- arch/x86/virt/vmx/tdx/tdx.c | 5 +++-- 2 files changed, 4 insertions(+), 3 deletions(-)
--- a/arch/x86/include/asm/tdx.h +++ b/arch/x86/include/asm/tdx.h @@ -97,7 +97,7 @@ void tdx_init(void);
typedef u64 (*sc_func_t)(u64 fn, struct tdx_module_args *args);
-static inline u64 sc_retry(sc_func_t func, u64 fn, +static __always_inline u64 sc_retry(sc_func_t func, u64 fn, struct tdx_module_args *args) { int retry = RDRAND_RETRY_LOOPS; --- a/arch/x86/virt/vmx/tdx/tdx.c +++ b/arch/x86/virt/vmx/tdx/tdx.c @@ -69,8 +69,9 @@ static inline void seamcall_err_ret(u64 args->r9, args->r10, args->r11); }
-static inline int sc_retry_prerr(sc_func_t func, sc_err_func_t err_func, - u64 fn, struct tdx_module_args *args) +static __always_inline int sc_retry_prerr(sc_func_t func, + sc_err_func_t err_func, + u64 fn, struct tdx_module_args *args) { u64 sret = sc_retry(func, fn, args);