Re: [rft] s2ram wakeup moves to .c, could fix few machines

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Rafael J. Wysocki wrote:
Index: linux-2.6/arch/x86/kernel/acpi/realmode/wakeup.S
===================================================================
--- /dev/null
+++ linux-2.6/arch/x86/kernel/acpi/realmode/wakeup.S
@@ -0,0 +1,122 @@
+/*
+ * ACPI wakeup real mode startup stub
+ */
+#include <asm/segment.h>
+#include <asm/msr-index.h>
+#include <asm/page_64.h>
+#include <asm/pgtable_64.h>
+
+	.code16
+	.section ".header", "a"
+
+/* This should match the structure in wakeup.h */
+		.globl	wakeup_header
+wakeup_header:
+video_mode:	.short	0	/* Video mode number */
+pmode_return:	.byte	0x66, 0xea	/* ljmpl */
+		.long	0	/* offset goes here */
+		.short	__KERNEL_CS

Missing a .short pad here... Pavel fixed that at some point, I thought.

+pmode_cr0:	.long	0	/* Saved %cr0 */
+pmode_cr3:	.long	0	/* Saved %cr3 */
+pmode_cr4:	.long	0	/* Saved %cr4 */
+pmode_efer:	.quad	0	/* Saved EFER */
+pmode_gdt:	.quad	0
+realmode_flags:	.long	0
+real_magic:	.long	0
+trampoline_segment:	.word 0
+signature:	.long	0x51ee1111
+
+	.text
+	.globl	_start
+	.code16
+wakeup_code:
+_start:
+	cli
+	cld
+
+	/* Set up segments */
+	movw	%cs, %ax
+	movw	%ax, %ds
+	movw	%ax, %es
+	movw	%ax, %ss
+
+	movl	$wakeup_stack_end, %esp
+
+	/* Clear the EFLAGS */
+	pushl	$0
+	popfl
+
+	/* Check header signature... */
+	movl	signature, %eax
+	cmpl	$0x51ee1111, %eax
+	jne	bogus_real_magic
+
+	/* Check we really have everything... */
+	movl	end_signature, %eax
+	cmpl	$0x65a22c82, %eax
+	jne	bogus_real_magic
+
+	/* Zero the bss */
+	xorl	%eax, %eax
+	movw	$__bss_start, %di
+	movw	$__bss_end + 3, %cx
+	subw	%di, %cx
+	shrw	$2, %cx
+	rep
+	stosl
+
+	/* Call the C code */
+	calll	main
+
+	/* Do any other stuff... */
+
+#ifndef CONFIG_64BIT
+	/* This could also be done in C code... */
+	movl	pmode_cr3, %eax
+	movl	%eax, %cr3
+
+	movl	pmode_cr4, %ecx
+	jecxz	1f
+	movl	%ecx, %cr4
+1:
+	movl	pmode_efer, %eax
+	movl	pmode_efer + 4, %edx
+	movl	%eax, %ecx
+	orl	%edx, %ecx
+	jz	1f
+	movl	$0xc0000080, %ecx
+	wrmsr
+1:
+
+	lgdtl	pmode_gdt
+
+	/* This really couldn't... */
+	movl	pmode_cr0, %eax
+	movl	%eax, %cr0
+	jmp	pmode_return
+#else
+	pushw	$0
+	pushw	trampoline_segment
+	pushw	$0
+	lret
+#endif
+
+bogus_real_magic:
+1:
+	hlt
+	jmp	1b
+
+	.data
+	.balign	4
+	.globl	HEAP, heap_end
+HEAP:
+	.long	wakeup_heap
+heap_end:
+	.long	wakeup_stack
+
+	.bss
+wakeup_heap:
+	.space	2048
+wakeup_stack:
+	.space	2048
+wakeup_stack_end:
Index: linux-2.6/arch/x86/kernel/acpi/realmode/wakeup.h
===================================================================
--- /dev/null
+++ linux-2.6/arch/x86/kernel/acpi/realmode/wakeup.h
@@ -0,0 +1,29 @@
+/*
+ * Definitions for the wakeup data structure at the head of the
+ * wakeup code.
+ */
+
+#ifndef ARCH_X86_KERNEL_ACPI_RM_WAKEUP_H
+#define ARCH_X86_KERNEL_ACPI_RM_WAKEUP_H
+
+#include <linux/types.h>
+
+/* This must match data at wakeup.S */
+struct wakeup_header {
+	u16 video_mode;		/* Video mode number */
+	u16 _jmp1;		/* ljmpl opcode, 32-bit only */
+	u32 pmode_entry;	/* Protected mode resume point, 32-bit only */
+	u16 _jmp2;		/* CS value, 32-bit only */
+	u32 pmode_cr0;		/* Protected mode cr0 */
+	u32 pmode_cr3;		/* Protected mode cr3 */
+	u32 pmode_cr4;		/* Protected mode cr4 */
+	u32 pmode_efer_low;	/* Protected mode EFER */
+	u32 pmode_efer_high;
+	u64 pmode_gdt;
+	u32 realmode_flags;
+	u32 real_magic;
+	u16 trampoline_segment;	/* segment with trampoline code, 64-bit only */
+	u32 signature;		/* To check we have correct structure */
+} __attribute__((__packed__));
+
+#endif /* ARCH_X86_KERNEL_ACPI_RM_WAKEUP_H */
Index: linux-2.6/arch/x86/kernel/acpi/realmode/wakeup.ld
===================================================================
--- /dev/null
+++ linux-2.6/arch/x86/kernel/acpi/realmode/wakeup.ld
@@ -0,0 +1,51 @@
+/*
+ * wakeup.ld
+ *
+ * Linker script for the real-mode wakeup code
+ */
+OUTPUT_FORMAT("elf32-i386", "elf32-i386", "elf32-i386")
+OUTPUT_ARCH(i386)
+ENTRY(_start)
+
+SECTIONS
+{
+	. = 0x3f00;
+	.header		: { *(.header) }
+
+	. = 0;
+	.text		: { *(.text*) }
+
+	. = ALIGN(16);
+	.rodata		: { *(.rodata*) }
+
+	.videocards	: {
+		video_cards = .;
+		*(.videocards)
+		video_cards_end = .;
+	}
+
+	. = ALIGN(16);
+	.data		: { *(.data*) }
+
+	.signature	: {
+		end_signature = .;
+		LONG(0x65a22c82)
+	}
+
+	. = ALIGN(16);
+	.bss		:
+	{
+		__bss_start = .;
+		*(.bss)
+		__bss_end = .;
+	}
+
+	. = ALIGN(16);
+	_end = .;
+
+	/DISCARD/ : { *(.note*) }
+
+	/* Adjust this as appropriate */
+	/* This allows 4 pages (16K) */
+	. = ASSERT(_end <= 0x4000, "Wakeup too big!");
+}
Index: linux-2.6/arch/x86/kernel/acpi/sleep.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/acpi/sleep.c
+++ linux-2.6/arch/x86/kernel/acpi/sleep.c
@@ -11,29 +11,84 @@
 #include <linux/cpumask.h>
#include <asm/smp.h>
+#include "realmode/wakeup.h"
/* address in low memory of the wakeup routine. */
-unsigned long acpi_wakeup_address = 0;
+static unsigned long acpi_realmode;
+unsigned long acpi_wakeup_address;
 unsigned long acpi_realmode_flags;
-extern char wakeup_start, wakeup_end;
+extern char wakeup_code_start, wakeup_code_end;
 extern unsigned long acpi_copy_wakeup_routine(unsigned long);
+extern unsigned long setup_trampoline(void);
+extern void wakeup_long64(void);
+
+extern unsigned long saved_video_mode;
+extern long saved_magic;
+extern volatile unsigned long init_rsp;
+extern void (*initial_code)(void);
+#ifndef CONFIG_64BIT
+extern int wakeup_pmode_return;
+extern char swsusp_pg_dir[PAGE_SIZE];
+#else
+static char temp_stack[10240];
+#endif
+
+extern unsigned long FASTCALL(acpi_copy_wakeup_routine(unsigned long));
/**
  * acpi_save_state_mem - save kernel state
  *
  * Create an identity mapped page table and copy the wakeup routine to
  * low memory.
+ *
+ * Note that this is too late to change acpi_wakeup_address.
  */
 int acpi_save_state_mem(void)
 {
-	if (!acpi_wakeup_address) {
-		printk(KERN_ERR "Could not allocate memory during boot, S3 disabled\n");
+	struct wakeup_header *header;
+
+	if (!acpi_realmode) {
+		printk(KERN_ERR "Could not allocate memory during boot, "
+		       "S3 disabled\n");
 		return -ENOMEM;
 	}
-	memcpy((void *)acpi_wakeup_address, &wakeup_start,
-	       &wakeup_end - &wakeup_start);
-	acpi_copy_wakeup_routine(acpi_wakeup_address);
+	memcpy((void *)acpi_realmode, &wakeup_code_start, 4*PAGE_SIZE);

Using a PAGE_SIZE multiplier here isn't a good thing...

+	header = (struct wakeup_header *)(acpi_realmode + 0x3f00);

... especially not with magic constants like this.

If you're putting the "header" at the end, then you should also replace the end_signature stuff since that's, then, redundant. Furthermore, by doing so, you're also padding the binary out to its maximum length, so you might as well just remove the .bss-clearing stuff.

It's not really clear to me why to do this what way...

+	if (header->signature != 0x51ee1111) {
+		printk(KERN_ERR "wakeup header does not match\n");
+		return -EINVAL;
+	}
+
+	header->video_mode = saved_video_mode;
+
+#ifndef CONFIG_64BIT
+	store_gdt(&header->pmode_gdt);
+
+	header->pmode_efer_low = nx_enabled;
+	if (header->pmode_efer_low & 1) {
+		/* This is strange, why not save efer, always? */
+		rdmsr(MSR_EFER, header->pmode_efer_low,
+			header->pmode_efer_high);
+	}

Yes, why not save EFER every time?

	-hpa
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