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authorLinus Torvalds <torvalds@linux-foundation.org>2016-07-07 20:46:48 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-07-07 20:46:48 -0700
commitc09230f30876589e246c83a4b4649e60534638cf (patch)
treed7543c83ee092bc386a261ab730eabe8f69705ec
parentac904ae6e6f0a56be7b9a1cf66fbd50dd025fb06 (diff)
parent7fe39a21557b251e101671f2c3f79558a756afef (diff)
downloadlinux-stericsson-c09230f30876589e246c83a4b4649e60534638cf.tar.gz
Merge tag 'pm-4.7-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fixes from Rafael Wysocki: "One fix for a recent cpuidle core change that, against all odds, introduced a functional regression on Power systems and the fix for the crash during resume from hibernation on x86-64 that has been in the works for the last few weeks (it actually was ready last week, but I wanted to allow the reporters to test if for some more time). Specifics: - Fix a recent performance regression on Power systems (powernv and pseries) introduced by a core cpuidle commit that decreased the precision of the last_residency conversion from nano- to microseconds, which should not matter in theory, but turned out to play not-so-well with the special "snooze" idle state on Power (Shreyas B Prabhu). - Fix a crash during resume from hibernation on x86-64 caused by possible corruption of the kernel text part of page tables in the last phase of image restoration exposed by a security-related change during the 4.3 development cycle (Rafael Wysocki)" * tag 'pm-4.7-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: cpuidle: Fix last_residency division x86/power/64: Fix kernel text mapping corruption during image restoration
-rw-r--r--arch/x86/power/hibernate_64.c97
-rw-r--r--arch/x86/power/hibernate_asm_64.S55
-rw-r--r--drivers/cpuidle/cpuidle.c12
3 files changed, 113 insertions, 51 deletions
diff --git a/arch/x86/power/hibernate_64.c b/arch/x86/power/hibernate_64.c
index 009947d419a6..f2b5e6a5cf95 100644
--- a/arch/x86/power/hibernate_64.c
+++ b/arch/x86/power/hibernate_64.c
@@ -19,6 +19,7 @@
#include <asm/mtrr.h>
#include <asm/sections.h>
#include <asm/suspend.h>
+#include <asm/tlbflush.h>
/* Defined in hibernate_asm_64.S */
extern asmlinkage __visible int restore_image(void);
@@ -28,6 +29,7 @@ extern asmlinkage __visible int restore_image(void);
* kernel's text (this value is passed in the image header).
*/
unsigned long restore_jump_address __visible;
+unsigned long jump_address_phys;
/*
* Value of the cr3 register from before the hibernation (this value is passed
@@ -37,7 +39,43 @@ unsigned long restore_cr3 __visible;
pgd_t *temp_level4_pgt __visible;
-void *relocated_restore_code __visible;
+unsigned long relocated_restore_code __visible;
+
+static int set_up_temporary_text_mapping(void)
+{
+ pmd_t *pmd;
+ pud_t *pud;
+
+ /*
+ * The new mapping only has to cover the page containing the image
+ * kernel's entry point (jump_address_phys), because the switch over to
+ * it is carried out by relocated code running from a page allocated
+ * specifically for this purpose and covered by the identity mapping, so
+ * the temporary kernel text mapping is only needed for the final jump.
+ * Moreover, in that mapping the virtual address of the image kernel's
+ * entry point must be the same as its virtual address in the image
+ * kernel (restore_jump_address), so the image kernel's
+ * restore_registers() code doesn't find itself in a different area of
+ * the virtual address space after switching over to the original page
+ * tables used by the image kernel.
+ */
+ pud = (pud_t *)get_safe_page(GFP_ATOMIC);
+ if (!pud)
+ return -ENOMEM;
+
+ pmd = (pmd_t *)get_safe_page(GFP_ATOMIC);
+ if (!pmd)
+ return -ENOMEM;
+
+ set_pmd(pmd + pmd_index(restore_jump_address),
+ __pmd((jump_address_phys & PMD_MASK) | __PAGE_KERNEL_LARGE_EXEC));
+ set_pud(pud + pud_index(restore_jump_address),
+ __pud(__pa(pmd) | _KERNPG_TABLE));
+ set_pgd(temp_level4_pgt + pgd_index(restore_jump_address),
+ __pgd(__pa(pud) | _KERNPG_TABLE));
+
+ return 0;
+}
static void *alloc_pgt_page(void *context)
{
@@ -59,9 +97,10 @@ static int set_up_temporary_mappings(void)
if (!temp_level4_pgt)
return -ENOMEM;
- /* It is safe to reuse the original kernel mapping */
- set_pgd(temp_level4_pgt + pgd_index(__START_KERNEL_map),
- init_level4_pgt[pgd_index(__START_KERNEL_map)]);
+ /* Prepare a temporary mapping for the kernel text */
+ result = set_up_temporary_text_mapping();
+ if (result)
+ return result;
/* Set up the direct mapping from scratch */
for (i = 0; i < nr_pfn_mapped; i++) {
@@ -78,19 +117,50 @@ static int set_up_temporary_mappings(void)
return 0;
}
+static int relocate_restore_code(void)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+
+ relocated_restore_code = get_safe_page(GFP_ATOMIC);
+ if (!relocated_restore_code)
+ return -ENOMEM;
+
+ memcpy((void *)relocated_restore_code, &core_restore_code, PAGE_SIZE);
+
+ /* Make the page containing the relocated code executable */
+ pgd = (pgd_t *)__va(read_cr3()) + pgd_index(relocated_restore_code);
+ pud = pud_offset(pgd, relocated_restore_code);
+ if (pud_large(*pud)) {
+ set_pud(pud, __pud(pud_val(*pud) & ~_PAGE_NX));
+ } else {
+ pmd_t *pmd = pmd_offset(pud, relocated_restore_code);
+
+ if (pmd_large(*pmd)) {
+ set_pmd(pmd, __pmd(pmd_val(*pmd) & ~_PAGE_NX));
+ } else {
+ pte_t *pte = pte_offset_kernel(pmd, relocated_restore_code);
+
+ set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_NX));
+ }
+ }
+ __flush_tlb_all();
+
+ return 0;
+}
+
int swsusp_arch_resume(void)
{
int error;
/* We have got enough memory and from now on we cannot recover */
- if ((error = set_up_temporary_mappings()))
+ error = set_up_temporary_mappings();
+ if (error)
return error;
- relocated_restore_code = (void *)get_safe_page(GFP_ATOMIC);
- if (!relocated_restore_code)
- return -ENOMEM;
- memcpy(relocated_restore_code, &core_restore_code,
- &restore_registers - &core_restore_code);
+ error = relocate_restore_code();
+ if (error)
+ return error;
restore_image();
return 0;
@@ -109,11 +179,12 @@ int pfn_is_nosave(unsigned long pfn)
struct restore_data_record {
unsigned long jump_address;
+ unsigned long jump_address_phys;
unsigned long cr3;
unsigned long magic;
};
-#define RESTORE_MAGIC 0x0123456789ABCDEFUL
+#define RESTORE_MAGIC 0x123456789ABCDEF0UL
/**
* arch_hibernation_header_save - populate the architecture specific part
@@ -126,7 +197,8 @@ int arch_hibernation_header_save(void *addr, unsigned int max_size)
if (max_size < sizeof(struct restore_data_record))
return -EOVERFLOW;
- rdr->jump_address = restore_jump_address;
+ rdr->jump_address = (unsigned long)&restore_registers;
+ rdr->jump_address_phys = __pa_symbol(&restore_registers);
rdr->cr3 = restore_cr3;
rdr->magic = RESTORE_MAGIC;
return 0;
@@ -142,6 +214,7 @@ int arch_hibernation_header_restore(void *addr)
struct restore_data_record *rdr = addr;
restore_jump_address = rdr->jump_address;
+ jump_address_phys = rdr->jump_address_phys;
restore_cr3 = rdr->cr3;
return (rdr->magic == RESTORE_MAGIC) ? 0 : -EINVAL;
}
diff --git a/arch/x86/power/hibernate_asm_64.S b/arch/x86/power/hibernate_asm_64.S
index 4400a43b9e28..3177c2bc26f6 100644
--- a/arch/x86/power/hibernate_asm_64.S
+++ b/arch/x86/power/hibernate_asm_64.S
@@ -44,9 +44,6 @@ ENTRY(swsusp_arch_suspend)
pushfq
popq pt_regs_flags(%rax)
- /* save the address of restore_registers */
- movq $restore_registers, %rax
- movq %rax, restore_jump_address(%rip)
/* save cr3 */
movq %cr3, %rax
movq %rax, restore_cr3(%rip)
@@ -57,31 +54,34 @@ ENTRY(swsusp_arch_suspend)
ENDPROC(swsusp_arch_suspend)
ENTRY(restore_image)
- /* switch to temporary page tables */
- movq $__PAGE_OFFSET, %rdx
- movq temp_level4_pgt(%rip), %rax
- subq %rdx, %rax
- movq %rax, %cr3
- /* Flush TLB */
- movq mmu_cr4_features(%rip), %rax
- movq %rax, %rdx
- andq $~(X86_CR4_PGE), %rdx
- movq %rdx, %cr4; # turn off PGE
- movq %cr3, %rcx; # flush TLB
- movq %rcx, %cr3;
- movq %rax, %cr4; # turn PGE back on
-
/* prepare to jump to the image kernel */
- movq restore_jump_address(%rip), %rax
- movq restore_cr3(%rip), %rbx
+ movq restore_jump_address(%rip), %r8
+ movq restore_cr3(%rip), %r9
+
+ /* prepare to switch to temporary page tables */
+ movq temp_level4_pgt(%rip), %rax
+ movq mmu_cr4_features(%rip), %rbx
/* prepare to copy image data to their original locations */
movq restore_pblist(%rip), %rdx
+
+ /* jump to relocated restore code */
movq relocated_restore_code(%rip), %rcx
jmpq *%rcx
/* code below has been relocated to a safe page */
ENTRY(core_restore_code)
+ /* switch to temporary page tables */
+ movq $__PAGE_OFFSET, %rcx
+ subq %rcx, %rax
+ movq %rax, %cr3
+ /* flush TLB */
+ movq %rbx, %rcx
+ andq $~(X86_CR4_PGE), %rcx
+ movq %rcx, %cr4; # turn off PGE
+ movq %cr3, %rcx; # flush TLB
+ movq %rcx, %cr3;
+ movq %rbx, %cr4; # turn PGE back on
.Lloop:
testq %rdx, %rdx
jz .Ldone
@@ -96,24 +96,17 @@ ENTRY(core_restore_code)
/* progress to the next pbe */
movq pbe_next(%rdx), %rdx
jmp .Lloop
+
.Ldone:
/* jump to the restore_registers address from the image header */
- jmpq *%rax
- /*
- * NOTE: This assumes that the boot kernel's text mapping covers the
- * image kernel's page containing restore_registers and the address of
- * this page is the same as in the image kernel's text mapping (it
- * should always be true, because the text mapping is linear, starting
- * from 0, and is supposed to cover the entire kernel text for every
- * kernel).
- *
- * code below belongs to the image kernel
- */
+ jmpq *%r8
+ /* code below belongs to the image kernel */
+ .align PAGE_SIZE
ENTRY(restore_registers)
FRAME_BEGIN
/* go back to the original page tables */
- movq %rbx, %cr3
+ movq %r9, %cr3
/* Flush TLB, including "global" things (vmalloc) */
movq mmu_cr4_features(%rip), %rax
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index a4d0059e232c..c73207abb5a4 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -173,7 +173,7 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
struct cpuidle_state *target_state = &drv->states[index];
bool broadcast = !!(target_state->flags & CPUIDLE_FLAG_TIMER_STOP);
- u64 time_start, time_end;
+ ktime_t time_start, time_end;
s64 diff;
/*
@@ -195,13 +195,13 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
sched_idle_set_state(target_state);
trace_cpu_idle_rcuidle(index, dev->cpu);
- time_start = local_clock();
+ time_start = ns_to_ktime(local_clock());
stop_critical_timings();
entered_state = target_state->enter(dev, drv, index);
start_critical_timings();
- time_end = local_clock();
+ time_end = ns_to_ktime(local_clock());
trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
/* The cpu is no longer idle or about to enter idle. */
@@ -217,11 +217,7 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
if (!cpuidle_state_is_coupled(drv, index))
local_irq_enable();
- /*
- * local_clock() returns the time in nanosecond, let's shift
- * by 10 (divide by 1024) to have microsecond based time.
- */
- diff = (time_end - time_start) >> 10;
+ diff = ktime_us_delta(time_end, time_start);
if (diff > INT_MAX)
diff = INT_MAX;