linux-kernel - [PATCH 03/29] x86/boot/e820: Simplify the PPro Erratum #50 workaround

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Message-ID: <20250421185210.3372306-4-mingo@kernel.org>
Date: Mon, 21 Apr 2025 20:51:43 +0200
From: Ingo Molnar <mingo@...nel.org>
To: linux-kernel@...r.kernel.org
Cc: Andy Shevchenko <andy@...nel.org>,
	Arnd Bergmann <arnd@...nel.org>,
	Borislav Petkov <bp@...en8.de>,
	Juergen Gross <jgross@...e.com>,
	"H . Peter Anvin" <hpa@...or.com>,
	Kees Cook <keescook@...omium.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Mike Rapoport <rppt@...nel.org>,
	Paul Menzel <pmenzel@...gen.mpg.de>,
	Peter Zijlstra <peterz@...radead.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...nel.org>,
	David Woodhouse <dwmw@...zon.co.uk>
Subject: [PATCH 03/29] x86/boot/e820: Simplify the PPro Erratum #50 workaround

No need to print out the table - users won't really be able
to tell much from it anyway and the messages around this
erratum are unnecessarily obtuse.

Instead clearly inform the user that a 256 kB hole is being
punched in their memory map at the 1.75 GB physical address.

Not that there are many PPro users left. :-)

Signed-off-by: Ingo Molnar <mingo@...nel.org>
Cc: Andy Shevchenko <andy@...nel.org>
Cc: Arnd Bergmann <arnd@...nel.org>
Cc: David Woodhouse <dwmw@...zon.co.uk>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Kees Cook <keescook@...omium.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Mike Rapoport (Microsoft) <rppt@...nel.org>
---
 arch/x86/kernel/setup.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 9d2a13b37833..83cc265140c0 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -988,11 +988,9 @@ void __init setup_arch(char **cmdline_p)
 	trim_bios_range();
 #ifdef CONFIG_X86_32
 	if (ppro_with_ram_bug()) {
-		e820__range_update(0x70000000ULL, 0x40000ULL, E820_TYPE_RAM,
-				  E820_TYPE_RESERVED);
+		pr_info("Applying PPro RAM bug workaround: punching 256 kB hole at 1.75 GB physical.\n");
+		e820__range_update(0x70000000ULL, 0x40000ULL, E820_TYPE_RAM, E820_TYPE_RESERVED);
 		e820__update_table(e820_table);
-		printk(KERN_INFO "fixed physical RAM map:\n");
-		e820__print_table("bad_ppro");
 	}
 #else
 	early_gart_iommu_check();
-- 
2.45.2