linux-kernel - [PATCH v2 3/4] x86/boot: split parsing of boot

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Message-ID: <20241206103031.737458-4-rppt@kernel.org>
Date: Fri,  6 Dec 2024 12:30:30 +0200
From: Mike Rapoport <rppt@...nel.org>
To: x86@...nel.org
Cc: Andy Lutomirski <luto@...nel.org>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Ingo Molnar <mingo@...hat.com>,
	Mike Rapoport <rppt@...nel.org>,
	Ning Sun <ning.sun@...el.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	linux-kernel@...r.kernel.org,
	tboot-devel@...ts.sourceforge.net
Subject: [PATCH v2 3/4] x86/boot: split parsing of boot_params into a helper function

From: "Mike Rapoport (Microsoft)" <rppt@...nel.org>

Makes setup_arch a bit easier to comprehend.

No functional changes.

Signed-off-by: Mike Rapoport (Microsoft) <rppt@...nel.org>
---
 arch/x86/kernel/setup.c | 72 +++++++++++++++++++++++------------------
 1 file changed, 41 insertions(+), 31 deletions(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index c34316a12897..d4e44f50f350 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -426,6 +426,46 @@ static void __init parse_setup_data(void)
 	}
 }
 
+/*
+ * Translate the fields of 'struct boot_param' into global variables
+ * representing these parameters.
+ */
+static void __init parse_boot_params(void)
+{
+	ROOT_DEV = old_decode_dev(boot_params.hdr.root_dev);
+	screen_info = boot_params.screen_info;
+	edid_info = boot_params.edid_info;
+#ifdef CONFIG_X86_32
+	apm_info.bios = boot_params.apm_bios_info;
+	ist_info = boot_params.ist_info;
+#endif
+	saved_video_mode = boot_params.hdr.vid_mode;
+	bootloader_type = boot_params.hdr.type_of_loader;
+	if ((bootloader_type >> 4) == 0xe) {
+		bootloader_type &= 0xf;
+		bootloader_type |= (boot_params.hdr.ext_loader_type+0x10) << 4;
+	}
+	bootloader_version  = bootloader_type & 0xf;
+	bootloader_version |= boot_params.hdr.ext_loader_ver << 4;
+
+#ifdef CONFIG_BLK_DEV_RAM
+	rd_image_start = boot_params.hdr.ram_size & RAMDISK_IMAGE_START_MASK;
+#endif
+#ifdef CONFIG_EFI
+	if (!strncmp((char *)&boot_params.efi_info.efi_loader_signature,
+		     EFI32_LOADER_SIGNATURE, 4)) {
+		set_bit(EFI_BOOT, &efi.flags);
+	} else if (!strncmp((char *)&boot_params.efi_info.efi_loader_signature,
+		     EFI64_LOADER_SIGNATURE, 4)) {
+		set_bit(EFI_BOOT, &efi.flags);
+		set_bit(EFI_64BIT, &efi.flags);
+	}
+#endif
+
+	if (!boot_params.hdr.root_flags)
+		root_mountflags &= ~MS_RDONLY;
+}
+
 static void __init memblock_x86_reserve_range_setup_data(void)
 {
 	struct setup_indirect *indirect;
@@ -803,35 +843,7 @@ void __init setup_arch(char **cmdline_p)
 
 	setup_olpc_ofw_pgd();
 
-	ROOT_DEV = old_decode_dev(boot_params.hdr.root_dev);
-	screen_info = boot_params.screen_info;
-	edid_info = boot_params.edid_info;
-#ifdef CONFIG_X86_32
-	apm_info.bios = boot_params.apm_bios_info;
-	ist_info = boot_params.ist_info;
-#endif
-	saved_video_mode = boot_params.hdr.vid_mode;
-	bootloader_type = boot_params.hdr.type_of_loader;
-	if ((bootloader_type >> 4) == 0xe) {
-		bootloader_type &= 0xf;
-		bootloader_type |= (boot_params.hdr.ext_loader_type+0x10) << 4;
-	}
-	bootloader_version  = bootloader_type & 0xf;
-	bootloader_version |= boot_params.hdr.ext_loader_ver << 4;
-
-#ifdef CONFIG_BLK_DEV_RAM
-	rd_image_start = boot_params.hdr.ram_size & RAMDISK_IMAGE_START_MASK;
-#endif
-#ifdef CONFIG_EFI
-	if (!strncmp((char *)&boot_params.efi_info.efi_loader_signature,
-		     EFI32_LOADER_SIGNATURE, 4)) {
-		set_bit(EFI_BOOT, &efi.flags);
-	} else if (!strncmp((char *)&boot_params.efi_info.efi_loader_signature,
-		     EFI64_LOADER_SIGNATURE, 4)) {
-		set_bit(EFI_BOOT, &efi.flags);
-		set_bit(EFI_64BIT, &efi.flags);
-	}
-#endif
+	parse_boot_params();
 
 	x86_init.oem.arch_setup();
 
@@ -855,8 +867,6 @@ void __init setup_arch(char **cmdline_p)
 
 	copy_edd();
 
-	if (!boot_params.hdr.root_flags)
-		root_mountflags &= ~MS_RDONLY;
 	setup_initial_init_mm(_text, _etext, _edata, (void *)_brk_end);
 
 	/*
-- 
2.45.2