From: Catalin Marinas <catalin.marinas@arm.com>
To: Andrey Konovalov <andreyknvl@google.com>
Cc: linux-arm-kernel@lists.infradead.org,
Marco Elver <elver@google.com>,
Elena Petrova <lenaptr@google.com>,
Kevin Brodsky <kevin.brodsky@arm.com>,
Will Deacon <will.deacon@arm.com>,
Branislav Rankov <Branislav.Rankov@arm.com>,
kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, Alexander Potapenko <glider@google.com>,
Evgenii Stepanov <eugenis@google.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Andrew Morton <akpm@linux-foundation.org>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Dmitry Vyukov <dvyukov@google.com>
Subject: Re: [PATCH v2 27/37] arm64: mte: Switch GCR_EL1 in kernel entry and exit
Date: Thu, 17 Sep 2020 17:52:21 +0100 [thread overview]
Message-ID: <20200917165221.GF10662@gaia> (raw)
In-Reply-To: <c801517c8c6c0b14ac2f5d9e189ff86fdbf1d495.1600204505.git.andreyknvl@google.com>
On Tue, Sep 15, 2020 at 11:16:09PM +0200, Andrey Konovalov wrote:
> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
> index eca06b8c74db..3602ac45d093 100644
> --- a/arch/arm64/kernel/cpufeature.c
> +++ b/arch/arm64/kernel/cpufeature.c
> @@ -1721,6 +1721,9 @@ static void cpu_enable_mte(struct arm64_cpu_capabilities const *cap)
>
> /* Enable in-kernel MTE only if KASAN_HW_TAGS is enabled */
> if (IS_ENABLED(CONFIG_KASAN_HW_TAGS)) {
> + /* Enable the kernel exclude mask for random tags generation */
> + write_sysreg_s((SYS_GCR_EL1_RRND | gcr_kernel_excl), SYS_GCR_EL1);
Nitpick: no need for extra braces, the comma has lower precedence.
> +
> /* Enable MTE Sync Mode for EL1 */
> sysreg_clear_set(sctlr_el1, SCTLR_ELx_TCF_MASK, SCTLR_ELx_TCF_SYNC);
> isb();
> diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
> index ff34461524d4..79a6848840bd 100644
> --- a/arch/arm64/kernel/entry.S
> +++ b/arch/arm64/kernel/entry.S
> @@ -175,6 +175,28 @@ alternative_else_nop_endif
> #endif
> .endm
>
> + .macro mte_restore_gcr, el, tsk, tmp, tmp2
> +#ifdef CONFIG_ARM64_MTE
> +alternative_if_not ARM64_MTE
> + b 1f
> +alternative_else_nop_endif
> + .if \el == 0
> + ldr \tmp, [\tsk, #THREAD_GCR_EL1_USER]
> + .else
> + ldr_l \tmp, gcr_kernel_excl
> + .endif
> + /*
> + * Calculate and set the exclude mask preserving
> + * the RRND (bit[16]) setting.
> + */
> + mrs_s \tmp2, SYS_GCR_EL1
> + bfi \tmp2, \tmp, #0, #16
> + msr_s SYS_GCR_EL1, \tmp2
> + isb
> +1:
> +#endif
> + .endm
> +
> .macro kernel_entry, el, regsize = 64
> .if \regsize == 32
> mov w0, w0 // zero upper 32 bits of x0
> @@ -214,6 +236,8 @@ alternative_else_nop_endif
>
> ptrauth_keys_install_kernel tsk, x20, x22, x23
>
> + mte_restore_gcr 1, tsk, x22, x23
> +
> scs_load tsk, x20
> .else
> add x21, sp, #S_FRAME_SIZE
> @@ -332,6 +356,8 @@ alternative_else_nop_endif
> /* No kernel C function calls after this as user keys are set. */
> ptrauth_keys_install_user tsk, x0, x1, x2
>
> + mte_restore_gcr 0, tsk, x0, x1
Some nitpicks on these macros to match the ptrauth_keys_* above. Define
separate mte_set_{user,kernel}_gcr macros with a common mte_set_gcr that
is used by both.
> +
> apply_ssbd 0, x0, x1
> .endif
>
> diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c
> index 858e75cfcaa0..1c7d963b5038 100644
> --- a/arch/arm64/kernel/mte.c
> +++ b/arch/arm64/kernel/mte.c
> @@ -18,10 +18,13 @@
>
> #include <asm/barrier.h>
> #include <asm/cpufeature.h>
> +#include <asm/kprobes.h>
What's this apparently random kprobes.h include?
> #include <asm/mte.h>
> #include <asm/ptrace.h>
> #include <asm/sysreg.h>
>
> +u64 gcr_kernel_excl __ro_after_init;
> +
> static void mte_sync_page_tags(struct page *page, pte_t *ptep, bool check_swap)
> {
> pte_t old_pte = READ_ONCE(*ptep);
> @@ -120,6 +123,13 @@ void *mte_set_mem_tag_range(void *addr, size_t size, u8 tag)
> return ptr;
> }
>
> +void mte_init_tags(u64 max_tag)
> +{
> + u64 incl = GENMASK(max_tag & MTE_TAG_MAX, 0);
> +
> + gcr_kernel_excl = ~incl & SYS_GCR_EL1_EXCL_MASK;
> +}
Do we need to set the actual GCR_EL1 register here? We may not get an
exception by the time KASAN starts using it.
--
Catalin
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next prev parent reply other threads:[~2020-09-17 16:53 UTC|newest]
Thread overview: 90+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-15 21:15 [PATCH v2 00/37] kasan: add hardware tag-based mode for arm64 Andrey Konovalov
2020-09-15 21:15 ` [PATCH v2 01/37] kasan: KASAN_VMALLOC depends on KASAN_GENERIC Andrey Konovalov
2020-09-15 21:15 ` [PATCH v2 02/37] kasan: group vmalloc code Andrey Konovalov
2020-09-15 21:15 ` [PATCH v2 03/37] kasan: shadow declarations only for software modes Andrey Konovalov
2020-09-15 21:15 ` [PATCH v2 04/37] kasan: rename (un)poison_shadow to (un)poison_memory Andrey Konovalov
2020-09-15 21:15 ` [PATCH v2 05/37] kasan: rename KASAN_SHADOW_* to KASAN_GRANULE_* Andrey Konovalov
2020-09-18 8:04 ` Alexander Potapenko
2020-09-18 10:42 ` Andrey Konovalov
2020-09-15 21:15 ` [PATCH v2 06/37] kasan: only build init.c for software modes Andrey Konovalov
2020-09-15 21:15 ` [PATCH v2 07/37] kasan: split out shadow.c from common.c Andrey Konovalov
2020-09-18 8:17 ` Alexander Potapenko
2020-09-18 10:39 ` Andrey Konovalov
2020-09-15 21:15 ` [PATCH v2 08/37] kasan: rename generic/tags_report.c files Andrey Konovalov
2020-09-15 21:15 ` [PATCH v2 09/37] kasan: don't duplicate config dependencies Andrey Konovalov
2020-09-15 21:15 ` [PATCH v2 10/37] kasan: hide invalid free check implementation Andrey Konovalov
2020-09-15 21:15 ` [PATCH v2 11/37] kasan: decode stack frame only with KASAN_STACK_ENABLE Andrey Konovalov
2020-09-15 21:15 ` [PATCH v2 12/37] kasan, arm64: only init shadow for software modes Andrey Konovalov
2020-09-17 17:05 ` Catalin Marinas
2020-09-15 21:15 ` [PATCH v2 13/37] kasan, arm64: only use kasan_depth " Andrey Konovalov
2020-09-17 17:05 ` Catalin Marinas
2020-09-15 21:15 ` [PATCH v2 14/37] kasan: rename addr_has_shadow to addr_has_metadata Andrey Konovalov
2020-09-15 21:15 ` [PATCH v2 15/37] kasan: rename print_shadow_for_address to print_memory_metadata Andrey Konovalov
2020-09-15 21:15 ` [PATCH v2 16/37] kasan: kasan_non_canonical_hook only for software modes Andrey Konovalov
2020-09-15 21:15 ` [PATCH v2 17/37] kasan: rename SHADOW layout macros to META Andrey Konovalov
2020-09-15 21:16 ` [PATCH v2 18/37] kasan: separate metadata_fetch_row for each mode Andrey Konovalov
2020-09-15 21:16 ` [PATCH v2 19/37] kasan: don't allow SW_TAGS with ARM64_MTE Andrey Konovalov
2020-09-17 17:05 ` Catalin Marinas
2020-09-15 21:16 ` [PATCH v2 20/37] kasan: rename tags.c to tags_sw.c Andrey Konovalov
2020-09-18 9:41 ` Alexander Potapenko
2020-09-18 9:44 ` Alexander Potapenko
2020-09-18 9:46 ` Alexander Potapenko
2020-09-18 10:42 ` Andrey Konovalov
2020-09-15 21:16 ` [PATCH v2 21/37] kasan: introduce CONFIG_KASAN_HW_TAGS Andrey Konovalov
2020-09-18 12:32 ` Marco Elver
2020-09-18 15:06 ` Andrey Konovalov
2020-09-18 15:36 ` Marco Elver
2020-09-18 15:45 ` Andrey Konovalov
2020-09-15 21:16 ` [PATCH v2 22/37] arm64: mte: Add in-kernel MTE helpers Andrey Konovalov
2020-09-17 13:46 ` Catalin Marinas
2020-09-17 14:21 ` Vincenzo Frascino
2020-09-18 9:36 ` Catalin Marinas
2020-09-22 10:16 ` Vincenzo Frascino
2020-09-17 16:17 ` Vincenzo Frascino
2020-09-17 17:07 ` Catalin Marinas
2020-09-15 21:16 ` [PATCH v2 23/37] arm64: kasan: Add arch layer for memory tagging helpers Andrey Konovalov
2020-09-17 17:05 ` Catalin Marinas
2020-09-18 13:00 ` Marco Elver
2020-09-18 14:56 ` Andrey Konovalov
2020-09-15 21:16 ` [PATCH v2 24/37] arm64: mte: Add in-kernel tag fault handler Andrey Konovalov
2020-09-17 14:03 ` Catalin Marinas
2020-09-17 14:24 ` Vincenzo Frascino
2020-09-17 14:59 ` Catalin Marinas
2020-09-15 21:16 ` [PATCH v2 25/37] arm64: kasan: Enable in-kernel MTE Andrey Konovalov
2020-09-17 16:35 ` Catalin Marinas
2020-09-15 21:16 ` [PATCH v2 26/37] arm64: mte: Convert gcr_user into an exclude mask Andrey Konovalov
2020-09-17 17:06 ` Catalin Marinas
2020-09-15 21:16 ` [PATCH v2 27/37] arm64: mte: Switch GCR_EL1 in kernel entry and exit Andrey Konovalov
2020-09-17 16:52 ` Catalin Marinas [this message]
2020-09-17 16:58 ` Catalin Marinas
2020-09-17 18:47 ` Vincenzo Frascino
2020-09-18 9:39 ` Catalin Marinas
2020-09-15 21:16 ` [PATCH v2 28/37] arm64: kasan: Enable TBI EL1 Andrey Konovalov
2020-09-17 16:54 ` Catalin Marinas
2020-09-15 21:16 ` [PATCH v2 29/37] arm64: kasan: Align allocations for HW_TAGS Andrey Konovalov
2020-09-17 17:06 ` Catalin Marinas
2020-09-15 21:16 ` [PATCH v2 30/37] kasan: define KASAN_GRANULE_SIZE " Andrey Konovalov
2020-09-15 21:16 ` [PATCH v2 31/37] kasan, x86, s390: update undef CONFIG_KASAN Andrey Konovalov
2020-09-18 10:52 ` Marco Elver
2020-09-18 15:07 ` Andrey Konovalov
2020-09-24 21:35 ` Andrey Konovalov
2020-09-15 21:16 ` [PATCH v2 32/37] kasan, arm64: expand CONFIG_KASAN checks Andrey Konovalov
2020-09-17 17:06 ` Catalin Marinas
2020-09-15 21:16 ` [PATCH v2 33/37] kasan, arm64: implement HW_TAGS runtime Andrey Konovalov
2020-09-17 17:06 ` Catalin Marinas
2020-09-18 10:46 ` Marco Elver
2020-09-18 12:28 ` Andrey Konovalov
2020-09-18 12:52 ` Marco Elver
2020-09-18 15:00 ` Andrey Konovalov
2020-09-18 15:19 ` Marco Elver
2020-09-18 15:52 ` Andrey Konovalov
2020-09-15 21:16 ` [PATCH v2 34/37] kasan, arm64: print report from tag fault handler Andrey Konovalov
2020-09-17 17:04 ` Catalin Marinas
2020-09-18 12:26 ` Andrey Konovalov
2020-09-15 21:16 ` [PATCH v2 35/37] kasan, slub: reset tags when accessing metadata Andrey Konovalov
2020-09-18 14:44 ` Marco Elver
2020-09-18 14:55 ` Andrey Konovalov
2020-09-18 15:29 ` Catalin Marinas
2020-09-15 21:16 ` [PATCH v2 36/37] kasan, arm64: enable CONFIG_KASAN_HW_TAGS Andrey Konovalov
2020-09-17 17:04 ` Catalin Marinas
2020-09-15 21:16 ` [PATCH v2 37/37] kasan: add documentation for hardware tag-based mode Andrey Konovalov
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