Commit 6bae499a authored Sep 21, 2018 by Zhimin Gu Committed by Rafael J. Wysocki Oct 03, 2018

x86-32, hibernate: Switch to relocated restore code during resume on 32bit system



On 64bit system, code should be executed in a safe page
during page restoring, as the page where instruction is
running during resume might be scribbled and causes issues.

Although on 32 bit, we only suspend resuming by same kernel
that did the suspend, we'd like to remove that restriction
in the future.

Porting corresponding code from
64bit system: Allocate a safe page, and copy the restore
code to it, then jump to the safe page to run the code.

Signed-off-by: Zhimin Gu <kookoo.gu@intel.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

parent 32aa2764

arch/x86/power/hibernate.c

+0 −2

Original line number	Diff line number	Diff line
		@@ -212,7 +212,6 @@ int arch_hibernation_header_restore(void *addr)
		return 0;
		}

		#ifdef CONFIG_X86_64
		int relocate_restore_code(void)
		{
		pgd_t *pgd;
		@@ -251,4 +250,3 @@ int relocate_restore_code(void)
		__flush_tlb_all();
		return 0;
		}
		#endif

arch/x86/power/hibernate_32.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -158,6 +158,10 @@ asmlinkage int swsusp_arch_resume(void)

		temp_pgt = __pa(resume_pg_dir);

		error = relocate_restore_code();
		if (error)
		return error;

		/* We have got enough memory and from now on we cannot recover */
		restore_image();
		return 0;

arch/x86/power/hibernate_asm_32.S

+7 −0

Original line number	Diff line number	Diff line
		@@ -39,6 +39,13 @@ ENTRY(restore_image)
		movl restore_cr3, %ebp

		movl mmu_cr4_features, %ecx

		/* jump to relocated restore code */
		movl relocated_restore_code, %eax
		jmpl *%eax

		/* code below has been relocated to a safe page */
		ENTRY(core_restore_code)
		movl temp_pgt, %eax
		movl %eax, %cr3