linux-kernel - [PATCH 28/36] cpuidle,tdx: Make tdx noinstr clean

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Message-ID: <20220608144517.696962976@infradead.org>
Date:   Wed, 08 Jun 2022 16:27:51 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     peterz@...radead.org
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Subject: [PATCH 28/36] cpuidle,tdx: Make tdx noinstr clean

vmlinux.o: warning: objtool: __halt+0x2c: call to hcall_func.constprop.0() leaves .noinstr.text section
vmlinux.o: warning: objtool: __halt+0x3f: call to __tdx_hypercall() leaves .noinstr.text section
vmlinux.o: warning: objtool: __tdx_hypercall+0x66: call to __tdx_hypercall_failed() leaves .noinstr.text section

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 arch/x86/coco/tdx/tdcall.S |    2 ++
 arch/x86/coco/tdx/tdx.c    |    5 +++--
 2 files changed, 5 insertions(+), 2 deletions(-)

--- a/arch/x86/coco/tdx/tdcall.S
+++ b/arch/x86/coco/tdx/tdcall.S
@@ -31,6 +31,8 @@
 					  TDX_R12 | TDX_R13 | \
 					  TDX_R14 | TDX_R15 )
 
+.section .noinstr.text, "ax"
+
 /*
  * __tdx_module_call()  - Used by TDX guests to request services from
  * the TDX module (does not include VMM services) using TDCALL instruction.
--- a/arch/x86/coco/tdx/tdx.c
+++ b/arch/x86/coco/tdx/tdx.c
@@ -53,8 +53,9 @@ static inline u64 _tdx_hypercall(u64 fn,
 }
 
 /* Called from __tdx_hypercall() for unrecoverable failure */
-void __tdx_hypercall_failed(void)
+noinstr void __tdx_hypercall_failed(void)
 {
+	instrumentation_begin();
 	panic("TDVMCALL failed. TDX module bug?");
 }
 
@@ -64,7 +65,7 @@ void __tdx_hypercall_failed(void)
  * Reusing the KVM EXIT_REASON macros makes it easier to connect the host and
  * guest sides of these calls.
  */
-static u64 hcall_func(u64 exit_reason)
+static __always_inline u64 hcall_func(u64 exit_reason)
 {
 	return exit_reason;
 }