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From: Arvind Sankar <nivedita@alum.mit.edu>
To: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Ard Biesheuvel <ardb@kernel.org>
Cc: linux-efi@vger.kernel.org, x86@kernel.org, linux-doc@vger.kernel.org
Subject: [PATCH 3/8] efi/x86: Factor GDT setup code into a function
Date: Thu, 30 Jan 2020 15:04:35 -0500	[thread overview]
Message-ID: <20200130200440.1796058-4-nivedita@alum.mit.edu> (raw)
In-Reply-To: <20200130200440.1796058-1-nivedita@alum.mit.edu>

Move GDT allocation and definition code into a function in preparation
to cleaning it up a bit.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
---
 arch/x86/boot/compressed/eboot.c | 191 ++++++++++++++++---------------
 1 file changed, 101 insertions(+), 90 deletions(-)

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index a0a2fd0528af..066125a18391 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -344,6 +344,105 @@ void setup_graphics(struct boot_params *boot_params)
 	}
 }
 
+static efi_status_t setup_gdt(struct desc_ptr *gdt)
+{
+	efi_status_t status;
+	struct desc_struct *desc;
+
+	gdt->size = 0x800;
+	status = efi_low_alloc(gdt->size, 8, (unsigned long *)&gdt->address);
+	if (status != EFI_SUCCESS) {
+		efi_printk("Failed to allocate memory for 'gdt'\n");
+		return status;
+	}
+
+	memset((char *)gdt->address, 0x0, gdt->size);
+	desc = (struct desc_struct *)gdt->address;
+
+	/* The first GDT is a dummy. */
+	desc++;
+
+	if (IS_ENABLED(CONFIG_X86_64)) {
+		/* __KERNEL32_CS */
+		desc->limit0	= 0xffff;
+		desc->base0	= 0x0000;
+		desc->base1	= 0x0000;
+		desc->type	= SEG_TYPE_CODE | SEG_TYPE_EXEC_READ;
+		desc->s		= DESC_TYPE_CODE_DATA;
+		desc->dpl	= 0;
+		desc->p		= 1;
+		desc->limit1	= 0xf;
+		desc->avl	= 0;
+		desc->l		= 0;
+		desc->d		= SEG_OP_SIZE_32BIT;
+		desc->g		= SEG_GRANULARITY_4KB;
+		desc->base2	= 0x00;
+
+		desc++;
+	} else {
+		/* Second entry is unused on 32-bit */
+		desc++;
+	}
+
+	/* __KERNEL_CS */
+	desc->limit0	= 0xffff;
+	desc->base0	= 0x0000;
+	desc->base1	= 0x0000;
+	desc->type	= SEG_TYPE_CODE | SEG_TYPE_EXEC_READ;
+	desc->s		= DESC_TYPE_CODE_DATA;
+	desc->dpl	= 0;
+	desc->p		= 1;
+	desc->limit1	= 0xf;
+	desc->avl	= 0;
+
+	if (IS_ENABLED(CONFIG_X86_64)) {
+		desc->l = 1;
+		desc->d = 0;
+	} else {
+		desc->l = 0;
+		desc->d = SEG_OP_SIZE_32BIT;
+	}
+	desc->g		= SEG_GRANULARITY_4KB;
+	desc->base2	= 0x00;
+	desc++;
+
+	/* __KERNEL_DS */
+	desc->limit0	= 0xffff;
+	desc->base0	= 0x0000;
+	desc->base1	= 0x0000;
+	desc->type	= SEG_TYPE_DATA | SEG_TYPE_READ_WRITE;
+	desc->s		= DESC_TYPE_CODE_DATA;
+	desc->dpl	= 0;
+	desc->p		= 1;
+	desc->limit1	= 0xf;
+	desc->avl	= 0;
+	desc->l		= 0;
+	desc->d		= SEG_OP_SIZE_32BIT;
+	desc->g		= SEG_GRANULARITY_4KB;
+	desc->base2	= 0x00;
+	desc++;
+
+	if (IS_ENABLED(CONFIG_X86_64)) {
+		/* Task segment value */
+		desc->limit0	= 0x0000;
+		desc->base0	= 0x0000;
+		desc->base1	= 0x0000;
+		desc->type	= SEG_TYPE_TSS;
+		desc->s		= 0;
+		desc->dpl	= 0;
+		desc->p		= 1;
+		desc->limit1	= 0x0;
+		desc->avl	= 0;
+		desc->l		= 0;
+		desc->d		= 0;
+		desc->g		= SEG_GRANULARITY_4KB;
+		desc->base2	= 0x00;
+		desc++;
+	}
+
+	return EFI_SUCCESS;
+}
+
 void startup_32(struct boot_params *boot_params);
 
 void __noreturn efi_stub_entry(efi_handle_t handle,
@@ -716,7 +815,6 @@ struct boot_params *efi_main(efi_handle_t handle,
 	struct desc_ptr gdt;
 	struct setup_header *hdr = &boot_params->hdr;
 	efi_status_t status;
-	struct desc_struct *desc;
 	unsigned long cmdline_paddr;
 
 	sys_table = sys_table_arg;
@@ -754,12 +852,9 @@ struct boot_params *efi_main(efi_handle_t handle,
 
 	setup_quirks(boot_params);
 
-	gdt.size = 0x800;
-	status = efi_low_alloc(gdt.size, 8, (unsigned long *)&gdt.address);
-	if (status != EFI_SUCCESS) {
-		efi_printk("Failed to allocate memory for 'gdt'\n");
+	status = setup_gdt(&gdt);
+	if (status != EFI_SUCCESS)
 		goto fail;
-	}
 
 	/*
 	 * If the kernel isn't already loaded at the preferred load
@@ -787,90 +882,6 @@ struct boot_params *efi_main(efi_handle_t handle,
 		goto fail;
 	}
 
-	memset((char *)gdt.address, 0x0, gdt.size);
-	desc = (struct desc_struct *)gdt.address;
-
-	/* The first GDT is a dummy. */
-	desc++;
-
-	if (IS_ENABLED(CONFIG_X86_64)) {
-		/* __KERNEL32_CS */
-		desc->limit0	= 0xffff;
-		desc->base0	= 0x0000;
-		desc->base1	= 0x0000;
-		desc->type	= SEG_TYPE_CODE | SEG_TYPE_EXEC_READ;
-		desc->s		= DESC_TYPE_CODE_DATA;
-		desc->dpl	= 0;
-		desc->p		= 1;
-		desc->limit1	= 0xf;
-		desc->avl	= 0;
-		desc->l		= 0;
-		desc->d		= SEG_OP_SIZE_32BIT;
-		desc->g		= SEG_GRANULARITY_4KB;
-		desc->base2	= 0x00;
-
-		desc++;
-	} else {
-		/* Second entry is unused on 32-bit */
-		desc++;
-	}
-
-	/* __KERNEL_CS */
-	desc->limit0	= 0xffff;
-	desc->base0	= 0x0000;
-	desc->base1	= 0x0000;
-	desc->type	= SEG_TYPE_CODE | SEG_TYPE_EXEC_READ;
-	desc->s		= DESC_TYPE_CODE_DATA;
-	desc->dpl	= 0;
-	desc->p		= 1;
-	desc->limit1	= 0xf;
-	desc->avl	= 0;
-
-	if (IS_ENABLED(CONFIG_X86_64)) {
-		desc->l = 1;
-		desc->d = 0;
-	} else {
-		desc->l = 0;
-		desc->d = SEG_OP_SIZE_32BIT;
-	}
-	desc->g		= SEG_GRANULARITY_4KB;
-	desc->base2	= 0x00;
-	desc++;
-
-	/* __KERNEL_DS */
-	desc->limit0	= 0xffff;
-	desc->base0	= 0x0000;
-	desc->base1	= 0x0000;
-	desc->type	= SEG_TYPE_DATA | SEG_TYPE_READ_WRITE;
-	desc->s		= DESC_TYPE_CODE_DATA;
-	desc->dpl	= 0;
-	desc->p		= 1;
-	desc->limit1	= 0xf;
-	desc->avl	= 0;
-	desc->l		= 0;
-	desc->d		= SEG_OP_SIZE_32BIT;
-	desc->g		= SEG_GRANULARITY_4KB;
-	desc->base2	= 0x00;
-	desc++;
-
-	if (IS_ENABLED(CONFIG_X86_64)) {
-		/* Task segment value */
-		desc->limit0	= 0x0000;
-		desc->base0	= 0x0000;
-		desc->base1	= 0x0000;
-		desc->type	= SEG_TYPE_TSS;
-		desc->s		= 0;
-		desc->dpl	= 0;
-		desc->p		= 1;
-		desc->limit1	= 0x0;
-		desc->avl	= 0;
-		desc->l		= 0;
-		desc->d		= 0;
-		desc->g		= SEG_GRANULARITY_4KB;
-		desc->base2	= 0x00;
-		desc++;
-	}
-
 	raw_local_irq_disable();
 	native_load_gdt(&gdt);
 
-- 
2.24.1


  parent reply	other threads:[~2020-01-30 20:04 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-30 20:04 [PATCH 0/8] Remove 64-bit GDT setup in efi_main + doc fixes Arvind Sankar
2020-01-30 20:04 ` [PATCH 1/8] efi/x86: Use C wrapper instead of inline assembly Arvind Sankar
2020-01-30 20:04 ` [PATCH 2/8] efi/x86: Allocate the GDT pointer on the stack Arvind Sankar
2020-01-30 20:04 ` Arvind Sankar [this message]
2020-01-30 20:04 ` [PATCH 4/8] efi/x86: Only setup the GDT for 32-bit kernel Arvind Sankar
2020-01-30 20:04 ` [PATCH 5/8] efi/x86: Allocate only the required 32 bytes for the GDT Arvind Sankar
2020-01-30 20:04 ` [PATCH 6/8] efi/x86: Change __KERNEL_{CS,DS} to __BOOT_{CS,DS} Arvind Sankar
2020-01-30 20:04 ` [PATCH 7/8] Documentation/x86/boot: Clarify segment requirements for EFI handover Arvind Sankar
2020-01-31 19:24   ` Arvind Sankar
2020-01-30 20:04 ` [PATCH 8/8] Documentation/x86/boot: Correct segment requirements for 64-bit boot Arvind Sankar
2020-01-31  8:42 ` [PATCH 0/8] Remove 64-bit GDT setup in efi_main + doc fixes Ard Biesheuvel
2020-01-31  9:31   ` Ard Biesheuvel
2020-01-31 19:10     ` Arvind Sankar
2020-02-02 17:13 ` [PATCH v2 0/7] x86/efi,boot: GDT handling cleanup/fixes Arvind Sankar
2020-02-02 17:13   ` [PATCH v2 1/7] x86/boot: Remove KEEP_SEGMENTS support Arvind Sankar
2020-02-02 17:13   ` [PATCH v2 2/7] efi/x86: Don't depend on firmware GDT layout Arvind Sankar
2020-02-02 17:54     ` Ard Biesheuvel
2020-02-02 18:18       ` Arvind Sankar
2020-02-02 17:13   ` [PATCH v2 3/7] x86/boot: Reload GDTR after copying to the end of the buffer Arvind Sankar
2020-02-02 17:13   ` [PATCH v2 4/7] x86/boot: Clear direction and interrupt flags in startup_64 Arvind Sankar
2020-02-02 17:13   ` [PATCH v2 5/7] efi/x86: Remove GDT setup from efi_main Arvind Sankar
2020-02-02 17:13   ` [PATCH v2 6/7] x86/boot: GDT limit value should be size - 1 Arvind Sankar
2020-02-02 17:13   ` [PATCH v2 7/7] x86/boot: Micro-optimize GDT loading instructions Arvind Sankar
2020-02-02 18:01   ` [PATCH v2 0/7] x86/efi,boot: GDT handling cleanup/fixes Ard Biesheuvel

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