From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To: linuxppc-dev@lists.ozlabs.org, mpe@ellerman.id.au
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
linuxram@us.ibm.com, bauerman@linux.ibm.com, npiggin@gmail.com
Subject: [PATCH v2 17/28] powerpc/book3s64/pkeys: Don't update SPRN_AMR when in kernel mode.
Date: Sat, 2 May 2020 16:52:18 +0530 [thread overview]
Message-ID: <20200502112229.545331-18-aneesh.kumar@linux.ibm.com> (raw)
In-Reply-To: <20200502112229.545331-1-aneesh.kumar@linux.ibm.com>
Now that kernel correctly store/restore userspace AMR/IAMR values, avoid
manipulating AMR and IAMR from the kernel on behalf of userspace.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
arch/powerpc/include/asm/book3s/64/kup.h | 23 ++++++++
arch/powerpc/include/asm/processor.h | 5 --
arch/powerpc/kernel/process.c | 4 --
arch/powerpc/kernel/traps.c | 6 --
arch/powerpc/mm/book3s64/pkeys.c | 71 ++++--------------------
5 files changed, 34 insertions(+), 75 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/64/kup.h b/arch/powerpc/include/asm/book3s/64/kup.h
index fe1818954e51..31eb0acddea9 100644
--- a/arch/powerpc/include/asm/book3s/64/kup.h
+++ b/arch/powerpc/include/asm/book3s/64/kup.h
@@ -174,6 +174,29 @@ extern u64 default_uamor;
extern u64 default_amr;
extern u64 default_iamr;
+/*
+ * For kernel thread that doesn't have thread.regs return
+ * default AMR/IAMR values.
+ */
+static inline u64 current_thread_amr(void)
+{
+ if (current->thread.regs)
+ return current->thread.regs->kuap;
+ return AMR_KUAP_BLOCKED;
+}
+
+static inline u64 current_thread_iamr(void)
+{
+ if (current->thread.regs)
+ return current->thread.regs->kuep;
+ return AMR_KUEP_BLOCKED;
+}
+
+static inline u64 read_uamor(void)
+{
+ return default_uamor;
+}
+
static inline void kuap_restore_user_amr(struct pt_regs *regs)
{
if (!mmu_has_feature(MMU_FTR_PKEY))
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index a51964b4ec42..591987da44e2 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -234,11 +234,6 @@ struct thread_struct {
struct thread_vr_state ckvr_state; /* Checkpointed VR state */
unsigned long ckvrsave; /* Checkpointed VRSAVE */
#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
-#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 */
#endif /* CONFIG_KVM_BOOK3S_32_HANDLER */
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 0ab9a8cf1bcb..682deeee421f 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -585,7 +585,6 @@ static void save_all(struct task_struct *tsk)
__giveup_spe(tsk);
msr_check_and_clear(msr_all_available);
- thread_pkey_regs_save(&tsk->thread);
}
void flush_all_to_thread(struct task_struct *tsk)
@@ -1097,8 +1096,6 @@ static inline void save_sprs(struct thread_struct *t)
t->tar = mfspr(SPRN_TAR);
}
#endif
-
- thread_pkey_regs_save(t);
}
static inline void restore_sprs(struct thread_struct *old_thread,
@@ -1139,7 +1136,6 @@ static inline void restore_sprs(struct thread_struct *old_thread,
mtspr(SPRN_TIDR, new_thread->tidr);
#endif
- thread_pkey_regs_restore(new_thread, old_thread);
}
struct task_struct *__switch_to(struct task_struct *prev,
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 3fca22276bb1..a47fb49b7af8 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -348,12 +348,6 @@ static bool exception_common(int signr, struct pt_regs *regs, int code,
current->thread.trap_nr = code;
- /*
- * Save all the pkey registers AMR/IAMR/UAMOR. Eg: Core dumps need
- * to capture the content, if the task gets killed.
- */
- thread_pkey_regs_save(¤t->thread);
-
return true;
}
diff --git a/arch/powerpc/mm/book3s64/pkeys.c b/arch/powerpc/mm/book3s64/pkeys.c
index 5012b57af808..0f4fc2876fc8 100644
--- a/arch/powerpc/mm/book3s64/pkeys.c
+++ b/arch/powerpc/mm/book3s64/pkeys.c
@@ -264,40 +264,17 @@ void pkey_mm_init(struct mm_struct *mm)
mm->context.execute_only_pkey = execute_only_key;
}
-static inline u64 read_amr(void)
+static inline void update_current_thread_amr(u64 value)
{
- return mfspr(SPRN_AMR);
+ current->thread.regs->kuap = value;
}
-static inline void write_amr(u64 value)
-{
- mtspr(SPRN_AMR, value);
-}
-
-static inline u64 read_iamr(void)
-{
- if (static_branch_unlikely(&execute_pkey_disabled))
- return 0x0UL;
-
- return mfspr(SPRN_IAMR);
-}
-
-static inline void write_iamr(u64 value)
+static inline void update_current_thread_iamr(u64 value)
{
if (static_branch_unlikely(&execute_pkey_disabled))
return;
- mtspr(SPRN_IAMR, value);
-}
-
-static inline u64 read_uamor(void)
-{
- return mfspr(SPRN_UAMOR);
-}
-
-static inline void write_uamor(u64 value)
-{
- mtspr(SPRN_UAMOR, value);
+ current->thread.regs->kuep = value;
}
static bool is_pkey_enabled(int pkey)
@@ -314,20 +291,21 @@ static bool is_pkey_enabled(int pkey)
return !!(uamor_pkey_bits);
}
+/* FIXME!! what happens to other threads AMR value? */
static inline void init_amr(int pkey, u8 init_bits)
{
u64 new_amr_bits = (((u64)init_bits & 0x3UL) << pkeyshift(pkey));
- u64 old_amr = read_amr() & ~((u64)(0x3ul) << pkeyshift(pkey));
+ u64 old_amr = current_thread_amr() & ~((u64)(0x3ul) << pkeyshift(pkey));
- write_amr(old_amr | new_amr_bits);
+ update_current_thread_amr(old_amr | new_amr_bits);
}
static inline void init_iamr(int pkey, u8 init_bits)
{
u64 new_iamr_bits = (((u64)init_bits & 0x1UL) << pkeyshift(pkey));
- u64 old_iamr = read_iamr() & ~((u64)(0x1ul) << pkeyshift(pkey));
+ u64 old_iamr = current_thread_iamr() & ~((u64)(0x1ul) << pkeyshift(pkey));
- write_iamr(old_iamr | new_iamr_bits);
+ update_current_thread_iamr(old_iamr | new_iamr_bits);
}
/*
@@ -360,33 +338,6 @@ int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
return 0;
}
-void thread_pkey_regs_save(struct thread_struct *thread)
-{
- if (!mmu_has_feature(MMU_FTR_PKEY))
- return;
-
- /*
- * TODO: Skip saving registers if @thread hasn't used any keys yet.
- */
- thread->amr = read_amr();
- thread->iamr = read_iamr();
- thread->uamor = read_uamor();
-}
-
-void thread_pkey_regs_restore(struct thread_struct *new_thread,
- struct thread_struct *old_thread)
-{
- if (!mmu_has_feature(MMU_FTR_PKEY))
- return;
-
- if (old_thread->amr != new_thread->amr)
- 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);
-}
-
int execute_only_pkey(struct mm_struct *mm)
{
if (static_branch_likely(&execute_pkey_disabled))
@@ -440,10 +391,10 @@ static bool pkey_access_permitted(int pkey, bool write, bool execute)
return true;
pkey_shift = pkeyshift(pkey);
- if (execute && !(read_iamr() & (IAMR_EX_BIT << pkey_shift)))
+ if (execute && !(current_thread_iamr() & (IAMR_EX_BIT << pkey_shift)))
return true;
- amr = read_amr(); /* Delay reading amr until absolutely needed */
+ amr = current_thread_amr();
return ((!write && !(amr & (AMR_RD_BIT << pkey_shift))) ||
(write && !(amr & (AMR_WR_BIT << pkey_shift))));
}
--
2.26.2
next prev parent reply other threads:[~2020-05-02 12:35 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-02 11:22 [PATCH v2 00/28] Kernel userspace access/execution prevention with hash translation Aneesh Kumar K.V
2020-05-02 11:22 ` [PATCH v2 01/28] powerpc/book3s64/pkeys: Enable MMU_FTR_PKEY Aneesh Kumar K.V
2020-05-02 11:22 ` [PATCH v2 02/28] powerpc/book3s64/kuep: Add MMU_FTR_KUEP Aneesh Kumar K.V
2020-05-02 11:22 ` [PATCH v2 03/28] powerpc/book3s64/pkeys: Use execute_pkey_disable static key Aneesh Kumar K.V
2020-05-02 11:22 ` [PATCH v2 04/28] powerpc/book3s64/pkeys: Use MMU_FTR_PKEY instead of pkey_disabled " Aneesh Kumar K.V
2020-05-02 11:22 ` [PATCH v2 05/28] powerpc/book3s64/kuap: Move KUAP related function outside radix Aneesh Kumar K.V
2020-05-02 11:22 ` [PATCH v2 06/28] powerpc/book3s64/kuep: Move KUEP " Aneesh Kumar K.V
2020-05-02 11:22 ` [PATCH v2 07/28] powerpc/book3s64/kuap: Rename MMU_FTR_RADIX_KUAP to MMU_FTR_KUAP Aneesh Kumar K.V
2020-05-02 11:22 ` [PATCH v2 08/28] powerpc/book3s64/kuap/kuep: Make KUAP and KUEP a subfeature of PPC_MEM_KEYS Aneesh Kumar K.V
2020-05-02 11:22 ` [PATCH v2 09/28] powerpc/book3s64/kuap: Move UAMOR setup to key init function Aneesh Kumar K.V
2020-05-02 11:22 ` [PATCH v2 10/28] powerpc/book3s64/kuap: Use Key 3 for kernel mapping with hash translation Aneesh Kumar K.V
2020-05-02 11:22 ` [PATCH v2 11/28] powerpc/exec: Set thread.regs early during exec Aneesh Kumar K.V
2020-05-02 11:22 ` [PATCH v2 12/28] powerpc/book3s64/pkeys: Store/restore userspace AMR correctly on entry and exit from kernel Aneesh Kumar K.V
2020-05-02 11:22 ` [PATCH v2 13/28] powerpc/book3s64/kuep: Store/restore userspace IAMR " Aneesh Kumar K.V
2020-05-02 11:22 ` [PATCH v2 14/28] powerpc/book3s64/pkeys: Inherit correctly on fork Aneesh Kumar K.V
2020-05-02 11:22 ` [PATCH v2 15/28] powerpc/book3s64/pkeys: Reset userspace AMR correctly on exec Aneesh Kumar K.V
2020-05-07 14:25 ` Aneesh Kumar K.V
2020-05-02 11:22 ` [PATCH v2 16/28] powerpc/ptrace-view: Use pt_regs values instead of thread_struct based one Aneesh Kumar K.V
2020-05-02 11:22 ` Aneesh Kumar K.V [this message]
2020-05-02 11:22 ` [PATCH v2 18/28] powerpc/book3s64/kuap: Restrict access to userspace based on userspace AMR Aneesh Kumar K.V
2020-05-02 11:22 ` [PATCH v2 19/28] powerpc/book3s64/kuap: Improve error reporting with KUAP Aneesh Kumar K.V
2020-05-02 11:22 ` [PATCH v2 20/28] powerpc/book3s64/kuap: Use Key 3 to implement KUAP with hash translation Aneesh Kumar K.V
2020-05-02 11:22 ` [PATCH v2 21/28] powerpc/book3s64/kuep: Use Key 3 to implement KUEP " Aneesh Kumar K.V
2020-05-02 11:22 ` [PATCH v2 22/28] powerpc/book3s64/hash/kuap: Enable kuap on hash Aneesh Kumar K.V
2020-05-02 11:22 ` [PATCH v2 23/28] powerpc/book3s64/hash/kuep: Enable KUEP " Aneesh Kumar K.V
2020-05-02 11:22 ` [PATCH v2 24/28] powerpc/book3s64/keys: Print information during boot Aneesh Kumar K.V
2020-05-02 11:22 ` [PATCH v2 25/28] powerpc/selftest/ptrave-pkey: Rename variables to make it easier to follow code Aneesh Kumar K.V
2020-05-02 11:22 ` [PATCH v2 26/28] powerpc/selftest/ptrace-pkey: Update the test to mark an invalid pkey correctly Aneesh Kumar K.V
2020-05-02 11:22 ` [PATCH v2 27/28] powerpc/selftest/ptrace-pkey: IAMR and uamor cannot be updated by ptrace Aneesh Kumar K.V
2020-05-02 11:22 ` [PATCH v2 28/28] powerpc/book3s64/keys/kuap: Reset AMR/IAMR values on kexec Aneesh Kumar K.V
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200502112229.545331-18-aneesh.kumar@linux.ibm.com \
--to=aneesh.kumar@linux.ibm.com \
--cc=bauerman@linux.ibm.com \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=linuxram@us.ibm.com \
--cc=mpe@ellerman.id.au \
--cc=npiggin@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.