linux-kernel - Re: [PATCH v4] x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernel

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Date:   Wed, 17 Apr 2019 11:02:47 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Dave Young <dyoung@...hat.com>,
        Junichi Nomura <j-nomura@...jp.nec.com>
Cc:     Chao Fan <fanc.fnst@...fujitsu.com>, Baoquan He <bhe@...hat.com>,
        Kairui Song <kasong@...hat.com>,
        "x86@...nel.org" <x86@...nel.org>,
        "kexec@...ts.infradead.org" <kexec@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4] x86/boot: Use efi_setup_data for searching RSDP on
 kexec-ed kernel

On Wed, Apr 17, 2019 at 10:54:34AM +0200, Borislav Petkov wrote:
> On Wed, Apr 17, 2019 at 03:02:50PM +0800, Dave Young wrote:
> > How about move it after console_init,
> 
> Sounds ok to me. That's still before KASLR gets setup and should work
> for Chao's movable regions too.

---
diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index c0d6c560df69..24e65a0f756d 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -351,9 +351,6 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
 	/* Clear flags intended for solely in-kernel use. */
 	boot_params->hdr.loadflags &= ~KASLR_FLAG;
 
-	/* Save RSDP address for later use. */
-	boot_params->acpi_rsdp_addr = get_rsdp_addr();
-
 	sanitize_boot_params(boot_params);
 
 	if (boot_params->screen_info.orig_video_mode == 7) {
@@ -368,6 +365,14 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
 	cols = boot_params->screen_info.orig_video_cols;
 
 	console_init();
+
+	/*
+	 * Save RSDP address for later use. Have this after console_init()
+	 * so that early debugging output from the RSDP parsing code can be
+	 * collected.
+	 */
+	boot_params->acpi_rsdp_addr = get_rsdp_addr();
+
 	debug_putstr("early console in extract_kernel\n");
 
 	free_mem_ptr     = heap;	/* Heap */

-- 
Regards/Gruss,
    Boris.

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