Messages in this thread Patch in this message | | | From | NOMURA JUNICHI(野村 淳一) <> | Subject | [PATCH 2/2] x86/boot: Add a message about ignored early NMIs | Date | Fri, 2 Feb 2024 03:51:58 +0000 |
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Commit
78a509fba9c9 ("x86/boot: Ignore NMIs during very early boot")
added an empty handler in early boot stage to avoid boot failure due to spurious NMIs.
Add a diagnostic message to show when early NMIs have occurred and/or what happened to them.
[ bp: Touchups. ]
Suggested-by: Borislav Petkov <bp@alien8.de> Suggested-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Jun'ichi Nomura <junichi.nomura@nec.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Link: https://lore.kernel.org/lkml/20231130103339.GCZWhlA196uRklTMNF@fat_crate.local
-- v2 * Moved variable declaration and definition to the right place based on comments from Kirill. No functional changes. v3 * Removed comment and updated message in the NMI handler. * Use error_putdec() helper.
diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c --- a/arch/x86/boot/compressed/ident_map_64.c +++ b/arch/x86/boot/compressed/ident_map_64.c @@ -389,5 +389,5 @@ void do_boot_page_fault(struct pt_regs *regs, unsigned long error_code) void do_boot_nmi_trap(struct pt_regs *regs, unsigned long error_code) { - /* Empty handler to ignore NMI during early boot */ + spurious_nmi_count++; } diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c --- a/arch/x86/boot/compressed/misc.c +++ b/arch/x86/boot/compressed/misc.c @@ -52,6 +52,7 @@ struct port_io_ops pio_ops; memptr free_mem_ptr; memptr free_mem_end_ptr; +int spurious_nmi_count; static char *vidmem; static int vidport; @@ -493,6 +494,12 @@ asmlinkage __visible void *extract_kernel(void *rmode, unsigned char *output) /* Disable exception handling before booting the kernel */ cleanup_exception_handling(); + if (spurious_nmi_count) { + error_putstr("Spurious early NMIs ignored: "); + error_putdec(spurious_nmi_count); + error_putstr("\n"); + } + return output + entry_offset; } diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h --- a/arch/x86/boot/compressed/misc.h +++ b/arch/x86/boot/compressed/misc.h @@ -59,6 +59,7 @@ extern char _head[], _end[]; /* misc.c */ extern memptr free_mem_ptr; extern memptr free_mem_end_ptr; +extern int spurious_nmi_count; void *malloc(int size); void free(void *where); void __putstr(const char *s); | |