From: Mark Rutland <mark.rutland@arm.com>
To: linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com,
will@kernel.org
Cc: mark.rutland@arm.com, robin.murphy@arm.com, james.morse@arm.com,
hch@lst.de
Subject: [PATCHv4 16/17] arm64: uaccess: remove redundant PAN toggling
Date: Fri, 13 Nov 2020 12:49:36 +0000 [thread overview]
Message-ID: <20201113124937.20574-17-mark.rutland@arm.com> (raw)
In-Reply-To: <20201113124937.20574-1-mark.rutland@arm.com>
Some code (e.g. futex) needs to make privileged accesses to userspace
memory, and uses uaccess_{enable,disable}_privileged() in order to
permit this. All other uaccess primitives use LDTR/STTR, and never need
to toggle PAN.
Remove the redundant PAN toggling.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
---
arch/arm64/include/asm/cpucaps.h | 1 -
arch/arm64/include/asm/uaccess.h | 59 +++++++++++++---------------------------
arch/arm64/kernel/cpufeature.c | 17 ------------
3 files changed, 19 insertions(+), 58 deletions(-)
diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h
index e7d98997c09c..ce7b7ada2c82 100644
--- a/arch/arm64/include/asm/cpucaps.h
+++ b/arch/arm64/include/asm/cpucaps.h
@@ -17,7 +17,6 @@
#define ARM64_WORKAROUND_834220 7
#define ARM64_HAS_NO_HW_PREFETCH 8
#define ARM64_HAS_UAO 9
-#define ARM64_ALT_PAN_NOT_UAO 10
#define ARM64_HAS_VIRT_HOST_EXTN 11
#define ARM64_WORKAROUND_CAVIUM_27456 12
#define ARM64_HAS_32BIT_EL0 13
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
index 8a4d9ed5eb51..d81c083967ed 100644
--- a/arch/arm64/include/asm/uaccess.h
+++ b/arch/arm64/include/asm/uaccess.h
@@ -159,41 +159,20 @@ static inline void __uaccess_enable_hw_pan(void)
CONFIG_ARM64_PAN));
}
-#define __uaccess_disable(alt) \
-do { \
- if (!uaccess_ttbr0_disable()) \
- asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), alt, \
- CONFIG_ARM64_PAN)); \
-} while (0)
-
-#define __uaccess_enable(alt) \
-do { \
- if (!uaccess_ttbr0_enable()) \
- asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), alt, \
- CONFIG_ARM64_PAN)); \
-} while (0)
-
static inline void uaccess_disable_privileged(void)
{
- __uaccess_disable(ARM64_HAS_PAN);
-}
+ if (uaccess_ttbr0_disable())
+ return;
-static inline void uaccess_enable_privileged(void)
-{
- __uaccess_enable(ARM64_HAS_PAN);
+ __uaccess_enable_hw_pan();
}
-/*
- * These functions are no-ops when UAO is present.
- */
-static inline void uaccess_disable_not_uao(void)
+static inline void uaccess_enable_privileged(void)
{
- __uaccess_disable(ARM64_ALT_PAN_NOT_UAO);
-}
+ if (uaccess_ttbr0_enable())
+ return;
-static inline void uaccess_enable_not_uao(void)
-{
- __uaccess_enable(ARM64_ALT_PAN_NOT_UAO);
+ __uaccess_disable_hw_pan();
}
/*
@@ -265,9 +244,9 @@ do { \
#define __raw_get_user(x, ptr, err) \
do { \
__chk_user_ptr(ptr); \
- uaccess_enable_not_uao(); \
+ uaccess_ttbr0_enable(); \
__raw_get_mem("ldtr", x, ptr, err); \
- uaccess_disable_not_uao(); \
+ uaccess_ttbr0_disable(); \
} while (0)
#define __get_user_error(x, ptr, err) \
@@ -338,9 +317,9 @@ do { \
#define __raw_put_user(x, ptr, err) \
do { \
__chk_user_ptr(ptr); \
- uaccess_enable_not_uao(); \
+ uaccess_ttbr0_enable(); \
__raw_put_mem("sttr", x, ptr, err); \
- uaccess_disable_not_uao(); \
+ uaccess_ttbr0_disable(); \
} while (0)
#define __put_user_error(x, ptr, err) \
@@ -378,10 +357,10 @@ extern unsigned long __must_check __arch_copy_from_user(void *to, const void __u
#define raw_copy_from_user(to, from, n) \
({ \
unsigned long __acfu_ret; \
- uaccess_enable_not_uao(); \
+ uaccess_ttbr0_enable(); \
__acfu_ret = __arch_copy_from_user((to), \
__uaccess_mask_ptr(from), (n)); \
- uaccess_disable_not_uao(); \
+ uaccess_ttbr0_disable(); \
__acfu_ret; \
})
@@ -389,10 +368,10 @@ extern unsigned long __must_check __arch_copy_to_user(void __user *to, const voi
#define raw_copy_to_user(to, from, n) \
({ \
unsigned long __actu_ret; \
- uaccess_enable_not_uao(); \
+ uaccess_ttbr0_enable(); \
__actu_ret = __arch_copy_to_user(__uaccess_mask_ptr(to), \
(from), (n)); \
- uaccess_disable_not_uao(); \
+ uaccess_ttbr0_disable(); \
__actu_ret; \
})
@@ -400,10 +379,10 @@ extern unsigned long __must_check __arch_copy_in_user(void __user *to, const voi
#define raw_copy_in_user(to, from, n) \
({ \
unsigned long __aciu_ret; \
- uaccess_enable_not_uao(); \
+ uaccess_ttbr0_enable(); \
__aciu_ret = __arch_copy_in_user(__uaccess_mask_ptr(to), \
__uaccess_mask_ptr(from), (n)); \
- uaccess_disable_not_uao(); \
+ uaccess_ttbr0_disable(); \
__aciu_ret; \
})
@@ -414,9 +393,9 @@ extern unsigned long __must_check __arch_clear_user(void __user *to, unsigned lo
static inline unsigned long __must_check __clear_user(void __user *to, unsigned long n)
{
if (access_ok(to, n)) {
- uaccess_enable_not_uao();
+ uaccess_ttbr0_enable();
n = __arch_clear_user(__uaccess_mask_ptr(to), n);
- uaccess_disable_not_uao();
+ uaccess_ttbr0_disable();
}
return n;
}
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 5e9732f3561e..5d7032625ff2 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -153,10 +153,6 @@ EXPORT_SYMBOL(cpu_hwcap_keys);
.width = 0, \
}
-/* meta feature for alternatives */
-static bool __maybe_unused
-cpufeature_pan_not_uao(const struct arm64_cpu_capabilities *entry, int __unused);
-
static void cpu_enable_cnp(struct arm64_cpu_capabilities const *cap);
static bool __system_matches_cap(unsigned int n);
@@ -1779,13 +1775,6 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
.min_field_value = 1,
},
#endif /* CONFIG_ARM64_UAO */
-#ifdef CONFIG_ARM64_PAN
- {
- .capability = ARM64_ALT_PAN_NOT_UAO,
- .type = ARM64_CPUCAP_SYSTEM_FEATURE,
- .matches = cpufeature_pan_not_uao,
- },
-#endif /* CONFIG_ARM64_PAN */
#ifdef CONFIG_ARM64_VHE
{
.desc = "Virtualization Host Extensions",
@@ -2726,12 +2715,6 @@ void __init setup_cpu_features(void)
ARCH_DMA_MINALIGN);
}
-static bool __maybe_unused
-cpufeature_pan_not_uao(const struct arm64_cpu_capabilities *entry, int __unused)
-{
- return (__system_matches_cap(ARM64_HAS_PAN) && !__system_matches_cap(ARM64_HAS_UAO));
-}
-
static void __maybe_unused cpu_enable_cnp(struct arm64_cpu_capabilities const *cap)
{
cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
--
2.11.0
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-11-13 12:53 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-13 12:49 [PATCHv4 00/17] arm64: remove set_fs() and friends Mark Rutland
2020-11-13 12:49 ` [PATCHv4 01/17] arm64: ensure ERET from kthread is illegal Mark Rutland
2020-11-13 12:49 ` [PATCHv4 02/17] arm64: add C wrappers for SET_PSTATE_*() Mark Rutland
2020-11-13 12:49 ` [PATCHv4 03/17] arm64: head.S: rename el2_setup -> init_kernel_el Mark Rutland
2020-11-13 12:49 ` [PATCHv4 04/17] arm64: head.S: cleanup SCTLR_ELx initialization Mark Rutland
2020-11-13 12:49 ` [PATCHv4 05/17] arm64: head.S: always initialize PSTATE Mark Rutland
2020-11-13 12:49 ` [PATCHv4 06/17] arm64: sdei: move uaccess logic to arch/arm64/ Mark Rutland
2020-11-16 17:42 ` Catalin Marinas
2020-11-26 18:42 ` James Morse
2020-11-13 12:49 ` [PATCHv4 07/17] arm64: sdei: explicitly simulate PAN/UAO entry Mark Rutland
2020-11-26 18:42 ` James Morse
2020-12-01 12:14 ` Mark Rutland
2020-11-13 12:49 ` [PATCHv4 08/17] arm64: uaccess: move uao_* alternatives to asm-uaccess.h Mark Rutland
2020-11-14 9:22 ` Christoph Hellwig
2020-11-16 12:25 ` Mark Rutland
2020-11-13 12:49 ` [PATCHv4 09/17] arm64: uaccess: rename privileged uaccess routines Mark Rutland
2020-11-13 12:49 ` [PATCHv4 10/17] arm64: uaccess: simplify __copy_user_flushcache() Mark Rutland
2020-11-13 12:49 ` [PATCHv4 11/17] arm64: uaccess: refactor __{get,put}_user Mark Rutland
2020-11-13 12:49 ` [PATCHv4 12/17] arm64: uaccess: split user/kernel routines Mark Rutland
2020-11-26 18:42 ` James Morse
2020-12-01 11:03 ` Mark Rutland
2020-12-02 12:19 ` Mark Rutland
2020-11-13 12:49 ` [PATCHv4 13/17] arm64: uaccess cleanup macro naming Mark Rutland
2020-11-13 12:49 ` [PATCHv4 14/17] arm64: uaccess: remove set_fs() Mark Rutland
2020-11-16 17:40 ` Catalin Marinas
2020-11-17 10:44 ` Mark Rutland
2020-11-17 10:54 ` Catalin Marinas
2020-11-17 10:57 ` Mark Rutland
2020-11-17 11:02 ` Catalin Marinas
2020-11-17 11:07 ` Mark Rutland
2020-11-17 11:10 ` Catalin Marinas
2020-11-26 18:42 ` James Morse
2020-11-26 18:42 ` James Morse
2020-12-01 12:30 ` Mark Rutland
2020-11-13 12:49 ` [PATCHv4 15/17] arm64: uaccess: remove addr_limit_user_check() Mark Rutland
2020-11-13 12:49 ` Mark Rutland [this message]
2020-11-13 12:49 ` [PATCHv4 17/17] arm64: uaccess: remove vestigal UAO support Mark Rutland
2020-11-25 19:10 ` [PATCHv4 00/17] arm64: remove set_fs() and friends Catalin Marinas
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=20201113124937.20574-17-mark.rutland@arm.com \
--to=mark.rutland@arm.com \
--cc=catalin.marinas@arm.com \
--cc=hch@lst.de \
--cc=james.morse@arm.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=robin.murphy@arm.com \
--cc=will@kernel.org \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).