UAMOR values are not application-specific. The kernel initializes
its value based on different reserved keys. Remove the thread-specific
UAMOR value and don't switch the UAMOR on context switch.
Move UAMOR initialization to key initialization code. Now that
KUAP/KUEP feature depends on PPC_MEM_KEYS, we can start to consolidate
all register initialization to keys init.
Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com>
---
arch/powerpc/include/asm/book3s/64/kup.h | 2 ++
arch/powerpc/include/asm/processor.h | 1 -
arch/powerpc/kernel/ptrace/ptrace-view.c | 17 ++++++++----
arch/powerpc/kernel/smp.c | 5 ++++
arch/powerpc/mm/book3s64/pkeys.c | 35 ++++++++++++++----------
5 files changed, 39 insertions(+), 21 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/64/kup.h
b/arch/powerpc/include/asm/book3s/64/kup.h
index 3a0e138d2735..942594745dfa 100644
--- a/arch/powerpc/include/asm/book3s/64/kup.h
+++ b/arch/powerpc/include/asm/book3s/64/kup.h
@@ -67,6 +67,8 @@
#include <asm/mmu.h>
#include <asm/ptrace.h>
+extern u64 default_uamor;
+
static inline void kuap_restore_amr(struct pt_regs *regs, unsigned long amr)
{
if (mmu_has_feature(MMU_FTR_KUAP) && unlikely(regs->kuap != amr)) {
diff --git a/arch/powerpc/include/asm/processor.h
b/arch/powerpc/include/asm/processor.h
index 52a67835057a..6ac12168f1fe 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -237,7 +237,6 @@ struct thread_struct {
#ifdef CONFIG_PPC_MEM_KEYS
unsigned long amr;
unsigned long iamr;
- unsigned long uamor;
#endif
#ifdef CONFIG_KVM_BOOK3S_32_HANDLER
void* kvm_shadow_vcpu; /* KVM internal data */
diff --git a/arch/powerpc/kernel/ptrace/ptrace-view.c
b/arch/powerpc/kernel/ptrace/ptrace-view.c
index caeb5822a8f4..689711eb018a 100644
--- a/arch/powerpc/kernel/ptrace/ptrace-view.c
+++ b/arch/powerpc/kernel/ptrace/ptrace-view.c
@@ -488,14 +488,22 @@ static int pkey_active(struct task_struct *target, const
struct user_regset *reg
static int pkey_get(struct task_struct *target, const struct user_regset
*regset,
unsigned int pos, unsigned int count, void *kbuf, void
__user *ubuf)
{
+ int ret;
+
BUILD_BUG_ON(TSO(amr) + sizeof(unsigned long) != TSO(iamr));
- BUILD_BUG_ON(TSO(iamr) + sizeof(unsigned long) != TSO(uamor));
if (!arch_pkeys_enabled())
return -ENODEV;
- return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
&target->thread.amr,
- 0, ELF_NPKEY * sizeof(unsigned long));
+ ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
&target->thread.amr,
+ 0, 2 * sizeof(unsigned long));
+ if (ret)
+ goto err_out;
+
+ ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &default_uamor,
+ 2 * sizeof(unsigned long), 3 *
sizeof(unsigned long));
+err_out:
+ return ret;
}
static int pkey_set(struct task_struct *target, const struct user_regset
*regset,
@@ -518,8 +526,7 @@ static int pkey_set(struct task_struct *target, const
struct user_regset *regset
return ret;
/* UAMOR determines which bits of the AMR can be set from userspace. */
- target->thread.amr = (new_amr & target->thread.uamor) |
- (target->thread.amr & ~target->thread.uamor);
+ target->thread.amr = (new_amr & default_uamor) | (target->thread.amr &
~default_uamor);
return 0;
}
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index c820c95162ff..eec40082599f 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -59,6 +59,7 @@
#include <asm/asm-prototypes.h>
#include <asm/cpu_has_feature.h>
#include <asm/ftrace.h>
+#include <asm/kup.h>
#ifdef DEBUG
#include <asm/udbg.h>
@@ -1256,6 +1257,10 @@ void start_secondary(void *unused)
mmgrab(&init_mm);
current->active_mm = &init_mm;
+#ifdef CONFIG_PPC_MEM_KEYS
+ mtspr(SPRN_UAMOR, default_uamor);
+#endif
+
smp_store_cpu_info(cpu);
set_dec(tb_ticks_per_jiffy);
preempt_disable();
diff --git a/arch/powerpc/mm/book3s64/pkeys.c b/arch/powerpc/mm/book3s64/pkeys.c
index aeecc8b8e11c..3f3593f85358 100644
--- a/arch/powerpc/mm/book3s64/pkeys.c
+++ b/arch/powerpc/mm/book3s64/pkeys.c
@@ -24,7 +24,7 @@ static u32 initial_allocation_mask; /* Bits set for the
initially allocated k
static u64 default_amr;
static u64 default_iamr;
/* Allow all keys to be modified by default */
-static u64 default_uamor = ~0x0UL;
+u64 default_uamor = ~0x0UL;
/*
* Key used to implement PROT_EXEC mmap. Denies READ/WRITE
* We pick key 2 because 0 is special key and 1 is reserved as per ISA.
@@ -113,8 +113,16 @@ void __init pkey_early_init_devtree(void)
/* scan the device tree for pkey feature */
pkeys_total = scan_pkey_feature();
if (!pkeys_total) {
- /* No support for pkey. Mark it disabled */
- return;
+ /*
+ * No key support but on radix we can use key 0
+ * to implement kuap.
+ */
+ if (early_radix_enabled())
+ /*
+ * Make sure userspace can't change the AMR
+ */
+ default_uamor = 0;
+ goto err_out;
}
cur_cpu_spec->mmu_features |= MMU_FTR_PKEY;
@@ -197,6 +205,12 @@ void __init pkey_early_init_devtree(void)
initial_allocation_mask |= reserved_allocation_mask;
pr_info("Enabling Memory keys with max key count %d", max_pkey);
+err_out:
+ /*
+ * Setup uamor on boot cpu
+ */
+ mtspr(SPRN_UAMOR, default_uamor);
+
return;
}
@@ -232,8 +246,9 @@ void __init setup_kuap(bool disabled)
cur_cpu_spec->mmu_features |= MMU_FTR_KUAP;
}
- /* Make sure userspace can't change the AMR */
- mtspr(SPRN_UAMOR, 0);
+ /*
+ * Set the default kernel AMR values on all cpus.
+ */
mtspr(SPRN_AMR, AMR_KUAP_BLOCKED);
isync();
}
@@ -278,11 +293,6 @@ static inline u64 read_uamor(void)
return mfspr(SPRN_UAMOR);
}
-static inline void write_uamor(u64 value)
-{
- mtspr(SPRN_UAMOR, value);
-}
-
static bool is_pkey_enabled(int pkey)
{
u64 uamor = read_uamor();
@@ -353,7 +363,6 @@ void thread_pkey_regs_save(struct thread_struct *thread)
*/
thread->amr = read_amr();
thread->iamr = read_iamr();
- thread->uamor = read_uamor();
}
void thread_pkey_regs_restore(struct thread_struct *new_thread,
@@ -366,8 +375,6 @@ void thread_pkey_regs_restore(struct thread_struct
*new_thread,
write_amr(new_thread->amr);
if (old_thread->iamr != new_thread->iamr)
write_iamr(new_thread->iamr);
- if (old_thread->uamor != new_thread->uamor)
- write_uamor(new_thread->uamor);
}
void thread_pkey_regs_init(struct thread_struct *thread)
@@ -377,11 +384,9 @@ void thread_pkey_regs_init(struct thread_struct *thread)
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)
--
2.26.2
