linux-kernel - [tip: x86/microcode] x86/microcode/AMD: Fix a -Wsometimes-uninitialized clang false positive

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Message-ID: <172234998969.2215.14054341190096493979.tip-bot2@tip-bot2>
Date: Tue, 30 Jul 2024 14:33:09 -0000
From: "tip-bot2 for Borislav Petkov (AMD)" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: kernel test robot <lkp@...el.com>, "Borislav Petkov (AMD)" <bp@...en8.de>,
 x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [tip: x86/microcode] x86/microcode/AMD: Fix a
 -Wsometimes-uninitialized clang false positive

The following commit has been merged into the x86/microcode branch of tip:

Commit-ID:     5343558a868e7e635b40baa2e46bf53df1a2d131
Gitweb:        https://git.kernel.org/tip/5343558a868e7e635b40baa2e46bf53df1a2d131
Author:        Borislav Petkov (AMD) <bp@...en8.de>
AuthorDate:    Tue, 30 Jul 2024 09:52:43 +02:00
Committer:     Borislav Petkov (AMD) <bp@...en8.de>
CommitterDate: Tue, 30 Jul 2024 09:52:43 +02:00

x86/microcode/AMD: Fix a -Wsometimes-uninitialized clang false positive

Initialize equiv_id in order to shut up:

  arch/x86/kernel/cpu/microcode/amd.c:714:6: warning: variable 'equiv_id' is \
  used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
        if (x86_family(bsp_cpuid_1_eax) < 0x17) {
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

because clang doesn't do interprocedural analysis for warnings to see
that this variable won't be used uninitialized.

Fixes: 94838d230a6c ("x86/microcode/AMD: Use the family,model,stepping encoded in the patch ID")
Reported-by: kernel test robot <lkp@...el.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202407291815.gJBST0P3-lkp@intel.com/
Signed-off-by: Borislav Petkov (AMD) <bp@...en8.de>
---
 arch/x86/kernel/cpu/microcode/amd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index 1f5d36f..f63b051 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -703,7 +703,7 @@ static struct ucode_patch *find_patch(unsigned int cpu)
 {
 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
 	u32 rev, dummy __always_unused;
-	u16 equiv_id;
+	u16 equiv_id = 0;
 
 	/* fetch rev if not populated yet: */
 	if (!uci->cpu_sig.rev) {