[v6,02/17] arm64: hibernate: pass the allocated pgdp to ttbr0
diff mbox series

Message ID 20191004185234.31471-3-pasha.tatashin@soleen.com
State New
Headers show
Series
  • arm64: MMU enabled kexec relocation
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Commit Message

Pavel Tatashin Oct. 4, 2019, 6:52 p.m. UTC
ttbr0 should be set to the beginning of pgdp, however, currently
in create_safe_exec_page it is set to pgdp after pgd_offset_raw(),
which works by accident.

Fixes: 0194e760f7d2 ("arm64: hibernate: avoid potential TLB conflict")

Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
---
 arch/arm64/kernel/hibernate.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Comments

James Morse Oct. 11, 2019, 6:17 p.m. UTC | #1
Hi Pavel,

On 04/10/2019 19:52, Pavel Tatashin wrote:
> ttbr0 should be set to the beginning of pgdp, however, currently
> in create_safe_exec_page it is set to pgdp after pgd_offset_raw(),
> which works by accident.
> 
> Fixes: 0194e760f7d2 ("arm64: hibernate: avoid potential TLB conflict")

(That was a 'break before make' fix, the affected code comes from:
 82869ac57b5d (""arm64: kernel: Add support for hibernate/suspend-to-disk))

But, it works in all one circumstances its used: we know all the top bits will be zero.
I agree its by accident and we should fix it.

I don't think we should send it to stable.
Please drop the fixes tag, with that:
Reviewed-by: James Morse <james.morse@arm.com>


Thanks,

James


[0] https://lore.kernel.org/linux-arm-kernel/ddd81093-89fc-5146-0b33-ad3bd9a1c10c@arm.com/
Pavel Tatashin Oct. 14, 2019, 2:11 p.m. UTC | #2
On 19-10-11 19:17:22, James Morse wrote:
> > Fixes: 0194e760f7d2 ("arm64: hibernate: avoid potential TLB conflict")
> 
> (That was a 'break before make' fix, the affected code comes from:
>  82869ac57b5d (""arm64: kernel: Add support for hibernate/suspend-to-disk))
> 
> But, it works in all one circumstances its used: we know all the top bits will be zero.
> I agree its by accident and we should fix it.
> 
> I don't think we should send it to stable.
> Please drop the fixes tag, with that:

OK

> Reviewed-by: James Morse <james.morse@arm.com>
Thank you!

Pasha

Patch
diff mbox series

diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c
index e0a7fce0e01c..d52f69462c8f 100644
--- a/arch/arm64/kernel/hibernate.c
+++ b/arch/arm64/kernel/hibernate.c
@@ -201,6 +201,7 @@  static int create_safe_exec_page(void *src_start, size_t length,
 				 gfp_t mask)
 {
 	int rc = 0;
+	pgd_t *trans_pgd;
 	pgd_t *pgdp;
 	pud_t *pudp;
 	pmd_t *pmdp;
@@ -215,7 +216,8 @@  static int create_safe_exec_page(void *src_start, size_t length,
 	memcpy((void *)dst, src_start, length);
 	__flush_icache_range(dst, dst + length);
 
-	pgdp = pgd_offset_raw(allocator(mask), dst_addr);
+	trans_pgd = allocator(mask);
+	pgdp = pgd_offset_raw(trans_pgd, dst_addr);
 	if (pgd_none(READ_ONCE(*pgdp))) {
 		pudp = allocator(mask);
 		if (!pudp) {
@@ -262,7 +264,7 @@  static int create_safe_exec_page(void *src_start, size_t length,
 	 */
 	cpu_set_reserved_ttbr0();
 	local_flush_tlb_all();
-	write_sysreg(phys_to_ttbr(virt_to_phys(pgdp)), ttbr0_el1);
+	write_sysreg(phys_to_ttbr(virt_to_phys(trans_pgd)), ttbr0_el1);
 	isb();
 
 	*phys_dst_addr = virt_to_phys((void *)dst);