diff mbox series

[RFC,16/25] powerpc/book3s64/pkeys: Reset userspace AMR correctly on exec

Message ID 20200427080507.1626327-17-aneesh.kumar@linux.ibm.com (mailing list archive)
State Superseded
Headers show
Series Kernel userspace access/execution prevention with hash translation | expand

Checks

Context Check Description
snowpatch_ozlabs/apply_patch warning Failed to apply on branch powerpc/merge (54dc28ff5e0b3585224d49a31b53e030342ca5c3)
snowpatch_ozlabs/apply_patch warning Failed to apply on branch powerpc/next (45591da765885f7320a111d290b3a28a23eed359)
snowpatch_ozlabs/apply_patch warning Failed to apply on branch linus/master (6a8b55ed4056ea5559ebe4f6a4b247f627870d4c)
snowpatch_ozlabs/apply_patch warning Failed to apply on branch powerpc/fixes (5990cdee689c6885b27c6d969a3d58b09002b0bc)
snowpatch_ozlabs/apply_patch warning Failed to apply on branch linux-next (8bdabd09ec86a993419c8c98a4f34c12bc902c6c)
snowpatch_ozlabs/apply_patch fail Failed to apply to any branch

Commit Message

Aneesh Kumar K V April 27, 2020, 8:04 a.m. UTC 
On fork, we inherit from the parent and on exec, we should switch to default_amr values.

Also, avoid changing the AMR register value within the kernel. The kernel now runs with
different AMR values.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
 arch/powerpc/include/asm/pkeys.h |  1 +
 arch/powerpc/kernel/process.c    |  3 ++-
 arch/powerpc/mm/book3s64/pkeys.c | 16 +---------------
 3 files changed, 4 insertions(+), 16 deletions(-)
diff mbox series

Patch

diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h
index 6e8157f78b52..cd1a03044814 100644
--- a/arch/powerpc/include/asm/pkeys.h
+++ b/arch/powerpc/include/asm/pkeys.h
@@ -13,6 +13,7 @@ 
 
 extern int max_pkey;
 extern u64 default_uamor;
+extern u64 default_amr;
 extern u32 reserved_allocation_mask; /* bits set for reserved keys */
 
 #define ARCH_VM_PKEY_FLAGS (VM_PKEY_BIT0 | VM_PKEY_BIT1 | VM_PKEY_BIT2 | \
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index fc4cc32d4726..9660bab1d99d 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1473,6 +1473,8 @@  void arch_setup_new_exec(void)
 		current->thread.regs = regs - 1;
 	}
 
+	current->thread.regs->kuap  = default_amr;
+	current->thread.regs->kuep  = default_iamr;
 }
 #endif
 
@@ -1827,7 +1829,6 @@  void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp)
 	current->thread.load_tm = 0;
 #endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
 
-	thread_pkey_regs_init(&current->thread);
 }
 EXPORT_SYMBOL(start_thread);
 
diff --git a/arch/powerpc/mm/book3s64/pkeys.c b/arch/powerpc/mm/book3s64/pkeys.c
index d0d781876c20..42ca7aa09d5b 100644
--- a/arch/powerpc/mm/book3s64/pkeys.c
+++ b/arch/powerpc/mm/book3s64/pkeys.c
@@ -20,7 +20,7 @@  int  max_pkey;			/* Maximum key value supported */
  */
 u32  reserved_allocation_mask;
 static u32  initial_allocation_mask;   /* Bits set for the initially allocated keys */
-static u64 default_amr;
+u64 default_amr;
 static u64 default_iamr;
 /* Allow all keys to be modified by default */
 u64 default_uamor = ~0x0UL;
@@ -387,20 +387,6 @@  void thread_pkey_regs_restore(struct thread_struct *new_thread,
 		write_uamor(new_thread->uamor);
 }
 
-void thread_pkey_regs_init(struct thread_struct *thread)
-{
-	if (!mmu_has_feature(MMU_FTR_PKEY))
-		return;
-
-	thread->amr   = default_amr;
-	thread->iamr  = default_iamr;
-	thread->uamor = default_uamor;
-
-	write_amr(default_amr);
-	write_iamr(default_iamr);
-	write_uamor(default_uamor);
-}
-
 int execute_only_pkey(struct mm_struct *mm)
 {
 	if (static_branch_likely(&execute_pkey_disabled))