x86/ia32: State that IA32 emulation is disabled

Issue a short message once, on the first try to load a 32-bit process to save people time when wondering why it won't load and trying to execute it, would say: -bash: ./strsep32: cannot execute binary file: Exec format error Signed-off-by: Borislav Petkov (AMD) <[email protected]> Reviewed-by: Nikolay Borisov <[email protected]> Link: https://lore.kernel.org/r/[email protected]
sirdarckcat · Dec 11, 2023 · f789383 · f789383
1 parent 79c603e
commit f789383
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Showing 2 changed files with 11 additions and 2 deletions.
diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
@@ -150,7 +150,7 @@ do {						\
 	((x)->e_machine == EM_X86_64)
 
 #define compat_elf_check_arch(x)					\
-	((elf_check_arch_ia32(x) && ia32_enabled()) ||			\
+	((elf_check_arch_ia32(x) && ia32_enabled_verbose()) ||		\
 	 (IS_ENABLED(CONFIG_X86_X32_ABI) && (x)->e_machine == EM_X86_64))
 
 static inline void elf_common_init(struct thread_struct *t,

diff --git a/arch/x86/include/asm/ia32.h b/arch/x86/include/asm/ia32.h
@@ -2,7 +2,6 @@
 #ifndef _ASM_X86_IA32_H
 #define _ASM_X86_IA32_H
 
-
 #ifdef CONFIG_IA32_EMULATION
 
 #include <linux/compat.h>
@@ -84,4 +83,14 @@ static inline bool ia32_enabled(void)
 
 #endif
 
+static inline bool ia32_enabled_verbose(void)
+{
+	bool enabled = ia32_enabled();
+
+	if (IS_ENABLED(CONFIG_IA32_EMULATION) && !enabled)
+		pr_notice_once("32-bit emulation disabled. You can reenable with ia32_emulation=on\n");
+
+	return enabled;
+}
+
 #endif /* _ASM_X86_IA32_H */