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Message-ID: <20240123112624.GBZa-iYP1l9SSYtr-V@fat_crate.local>
Date: Tue, 23 Jan 2024 12:26:24 +0100
From: Borislav Petkov <bp@...en8.de>
To: NOMURA JUNICHI(野村 淳一) <junichi.nomura@....com>
Cc: "kirill.shutemov@...ux.intel.com" <kirill.shutemov@...ux.intel.com>,
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Subject: Re: [PATCH v2] x86/boot: Add a message about ignored early NMIs
On Mon, Jan 15, 2024 at 08:57:45AM +0000, NOMURA JUNICHI(野村 淳一) wrote:
> + if (spurious_nmi_count) {
> + error_putstr("Spurious early NMI ignored. Number of NMIs: 0x");
> + error_puthex(spurious_nmi_count);
> + error_putstr("\n");
Uff, that's just silly:
Spurious early NMIs ignored: 0x0000000000000017
Would you like to add a error_putnum() or so in a prepatch which would
make this output
Spurious early NMIs ignored: 23.
?
So that it is human readable and doesn't make me wonder what that hex
value is supposed to mean?
Thx.
Btw, please use this version when sending next time:
---
From: =?UTF-8?q?NOMURA=20JUNICHI=28=E9=87=8E=E6=9D=91=20=E6=B7=B3=E4=B8=80?=
=?UTF-8?q?=29?= <junichi.nomura@....com>
Date: Mon, 15 Jan 2024 08:57:45 +0000
Subject: [PATCH] x86/boot: Add a message about ignored early NMIs
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@...en8.de>
Suggested-by: H. Peter Anvin <hpa@...or.com>
Signed-off-by: Jun'ichi Nomura <junichi.nomura@....com>
Signed-off-by: Borislav Petkov (AMD) <bp@...en8.de>
Acked-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
Link: https://lore.kernel.org/lkml/20231130103339.GCZWhlA196uRklTMNF@fat_crate.local
---
arch/x86/boot/compressed/ident_map_64.c | 2 +-
arch/x86/boot/compressed/misc.c | 7 +++++++
arch/x86/boot/compressed/misc.h | 1 +
3 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c
index ff09ca6dbb87..909f2a35b60c 100644
--- 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
index b99e08e6815b..e7f4eb24a9a4 100644
--- 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: 0x");
+ error_puthex(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
index bc2f0f17fb90..b858d6aa648c 100644
--- 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);
--
2.43.0
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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