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arm64: hibernate: preserve kdump image around hibernation

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Since arch_kexec_protect_crashkres() removes a mapping for crash dump
kernel image, the loaded data won't be preserved around hibernation.

In this patch, helper functions, crash_prepare_suspend()/
crash_post_resume(), are additionally called before/after hibernation so
that the relevant memory segments will be mapped again and preserved just
as the others are.

In addition, to minimize the size of hibernation image, crash_is_nosave()
is added to pfn_is_nosave() in order to recognize only the pages that hold
loaded crash dump kernel image as saveable. Hibernation excludes any pages
that are marked as Reserved and yet "nosave."

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
AKASHI Takahiro
2017-04-03 11:24:35 +09:00
committed by Catalin Marinas
parent 98d2e1539b
commit 254a41c0ba
4 changed files with 117 additions and 1 deletions
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10
arch/arm64/kernel/hibernate.c
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@@ -28,6 +28,7 @@
#include <asm/cacheflush.h>
#include <asm/cputype.h>
#include <asm/irqflags.h>
#include <asm/kexec.h>
#include <asm/memory.h>
#include <asm/mmu_context.h>
#include <asm/pgalloc.h>
@@ -102,7 +103,8 @@ int pfn_is_nosave(unsigned long pfn)
unsigned long nosave_begin_pfn = sym_to_pfn(&__nosave_begin);
unsigned long nosave_end_pfn = sym_to_pfn(&__nosave_end - 1);
return (pfn >= nosave_begin_pfn) && (pfn <= nosave_end_pfn);
return ((pfn >= nosave_begin_pfn) && (pfn <= nosave_end_pfn)) ||
crash_is_nosave(pfn);
}
void notrace save_processor_state(void)
@@ -286,6 +288,9 @@ int swsusp_arch_suspend(void)
local_dbg_save(flags);
if (__cpu_suspend_enter(&state)) {
/* make the crash dump kernel image visible/saveable */
crash_prepare_suspend();
sleep_cpu = smp_processor_id();
ret = swsusp_save();
} else {
@@ -297,6 +302,9 @@ int swsusp_arch_suspend(void)
if (el2_reset_needed())
dcache_clean_range(__hyp_idmap_text_start, __hyp_idmap_text_end);
/* make the crash dump kernel image protected again */
crash_post_resume();
/*
* Tell the hibernation core that we've just restored
* the memory