Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 225 insertions, 0 deletions

diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S
new file mode 100644
index 000000000..659fad53c
--- /dev/null
+++ b/arch/x86/boot/compressed/head_32.S
@@ -0,0 +1,225 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ *  linux/boot/head.S
+ *
+ *  Copyright (C) 1991, 1992, 1993  Linus Torvalds
+ */
+
+/*
+ *  head.S contains the 32-bit startup code.
+ *
+ * NOTE!!! Startup happens at absolute address 0x00001000, which is also where
+ * the page directory will exist. The startup code will be overwritten by
+ * the page directory. [According to comments etc elsewhere on a compressed
+ * kernel it will end up at 0x1000 + 1Mb I hope so as I assume this. - AC]
+ *
+ * Page 0 is deliberately kept safe, since System Management Mode code in
+ * laptops may need to access the BIOS data stored there.  This is also
+ * useful for future device drivers that either access the BIOS via VM86
+ * mode.
+ */
+
+/*
+ * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
+ */
+	.text
+
+#include <linux/init.h>
+#include <linux/linkage.h>
+#include <asm/segment.h>
+#include <asm/page_types.h>
+#include <asm/boot.h>
+#include <asm/asm-offsets.h>
+#include <asm/bootparam.h>
+
+/*
+ * These symbols needed to be marked as .hidden to prevent the BFD linker from
+ * generating R_386_32 (rather than R_386_RELATIVE) relocations for them when
+ * the 32-bit compressed kernel is linked as PIE. This is no longer necessary,
+ * but it doesn't hurt to keep them .hidden.
+ */
+	.hidden _bss
+	.hidden _ebss
+	.hidden _end
+
+	__HEAD
+SYM_FUNC_START(startup_32)
+	cld
+	cli
+
+/*
+ * Calculate the delta between where we were compiled to run
+ * at and where we were actually loaded at.  This can only be done
+ * with a short local call on x86.  Nothing  else will tell us what
+ * address we are running at.  The reserved chunk of the real-mode
+ * data at 0x1e4 (defined as a scratch field) are used as the stack
+ * for this calculation. Only 4 bytes are needed.
+ */
+	leal	(BP_scratch+4)(%esi), %esp
+	call	1f
+1:	popl	%edx
+	addl	$_GLOBAL_OFFSET_TABLE_+(.-1b), %edx
+
+	/* Load new GDT */
+	leal	gdt@GOTOFF(%edx), %eax
+	movl	%eax, 2(%eax)
+	lgdt	(%eax)
+
+	/* Load segment registers with our descriptors */
+	movl	$__BOOT_DS, %eax
+	movl	%eax, %ds
+	movl	%eax, %es
+	movl	%eax, %fs
+	movl	%eax, %gs
+	movl	%eax, %ss
+
+/*
+ * %edx contains the address we are loaded at by the boot loader (plus the
+ * offset to the GOT).  The below code calculates %ebx to be the address where
+ * we should move the kernel image temporarily for safe in-place decompression
+ * (again, plus the offset to the GOT).
+ *
+ * %ebp is calculated to be the address that the kernel will be decompressed to.
+ */
+
+#ifdef CONFIG_RELOCATABLE
+	leal	startup_32@GOTOFF(%edx), %ebx
+
+#ifdef CONFIG_EFI_STUB
+/*
+ * If we were loaded via the EFI LoadImage service, startup_32() will be at an
+ * offset to the start of the space allocated for the image. efi_pe_entry() will
+ * set up image_offset to tell us where the image actually starts, so that we
+ * can use the full available buffer.
+ *	image_offset = startup_32 - image_base
+ * Otherwise image_offset will be zero and has no effect on the calculations.
+ */
+	subl    image_offset@GOTOFF(%edx), %ebx
+#endif
+
+	movl	BP_kernel_alignment(%esi), %eax
+	decl	%eax
+	addl    %eax, %ebx
+	notl	%eax
+	andl    %eax, %ebx
+	cmpl	$LOAD_PHYSICAL_ADDR, %ebx
+	jae	1f
+#endif
+	movl	$LOAD_PHYSICAL_ADDR, %ebx
+1:
+
+	movl	%ebx, %ebp	// Save the output address for later
+	/* Target address to relocate to for decompression */
+	addl    BP_init_size(%esi), %ebx
+	subl    $_end@GOTOFF, %ebx
+
+	/* Set up the stack */
+	leal	boot_stack_end@GOTOFF(%ebx), %esp
+
+	/* Zero EFLAGS */
+	pushl	$0
+	popfl
+
+/*
+ * Copy the compressed kernel to the end of our buffer
+ * where decompression in place becomes safe.
+ */
+	pushl	%esi
+	leal	(_bss@GOTOFF-4)(%edx), %esi
+	leal	(_bss@GOTOFF-4)(%ebx), %edi
+	movl	$(_bss - startup_32), %ecx
+	shrl	$2, %ecx
+	std
+	rep	movsl
+	cld
+	popl	%esi
+
+	/*
+	 * The GDT may get overwritten either during the copy we just did or
+	 * during extract_kernel below. To avoid any issues, repoint the GDTR
+	 * to the new copy of the GDT.
+	 */
+	leal	gdt@GOTOFF(%ebx), %eax
+	movl	%eax, 2(%eax)
+	lgdt	(%eax)
+
+/*
+ * Jump to the relocated address.
+ */
+	leal	.Lrelocated@GOTOFF(%ebx), %eax
+	jmp	*%eax
+SYM_FUNC_END(startup_32)
+
+#ifdef CONFIG_EFI_STUB
+SYM_FUNC_START(efi32_stub_entry)
+SYM_FUNC_START_ALIAS(efi_stub_entry)
+	add	$0x4, %esp
+	movl	8(%esp), %esi	/* save boot_params pointer */
+	call	efi_main
+	/* efi_main returns the possibly relocated address of startup_32 */
+	jmp	*%eax
+SYM_FUNC_END(efi32_stub_entry)
+SYM_FUNC_END_ALIAS(efi_stub_entry)
+#endif
+
+	.text
+SYM_FUNC_START_LOCAL_NOALIGN(.Lrelocated)
+
+/*
+ * Clear BSS (stack is currently empty)
+ */
+	xorl	%eax, %eax
+	leal	_bss@GOTOFF(%ebx), %edi
+	leal	_ebss@GOTOFF(%ebx), %ecx
+	subl	%edi, %ecx
+	shrl	$2, %ecx
+	rep	stosl
+
+/*
+ * Do the extraction, and jump to the new kernel..
+ */
+	/* push arguments for extract_kernel: */
+
+	pushl	output_len@GOTOFF(%ebx)	/* decompressed length, end of relocs */
+	pushl	%ebp			/* output address */
+	pushl	input_len@GOTOFF(%ebx)	/* input_len */
+	leal	input_data@GOTOFF(%ebx), %eax
+	pushl	%eax			/* input_data */
+	leal	boot_heap@GOTOFF(%ebx), %eax
+	pushl	%eax			/* heap area */
+	pushl	%esi			/* real mode pointer */
+	call	extract_kernel		/* returns kernel location in %eax */
+	addl	$24, %esp
+
+/*
+ * Jump to the extracted kernel.
+ */
+	xorl	%ebx, %ebx
+	jmp	*%eax
+SYM_FUNC_END(.Lrelocated)
+
+	.data
+	.balign	8
+SYM_DATA_START_LOCAL(gdt)
+	.word	gdt_end - gdt - 1
+	.long	0
+	.word	0
+	.quad	0x0000000000000000	/* Reserved */
+	.quad	0x00cf9a000000ffff	/* __KERNEL_CS */
+	.quad	0x00cf92000000ffff	/* __KERNEL_DS */
+SYM_DATA_END_LABEL(gdt, SYM_L_LOCAL, gdt_end)
+
+#ifdef CONFIG_EFI_STUB
+SYM_DATA(image_offset, .long 0)
+#endif
+
+/*
+ * Stack and heap for uncompression
+ */
+	.bss
+	.balign 4
+boot_heap:
+	.fill BOOT_HEAP_SIZE, 1, 0
+boot_stack:
+	.fill BOOT_STACK_SIZE, 1, 0
+boot_stack_end: