lkml.org 
[lkml]   [2018]   [Oct]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[RFC 13/17] arm64: install user ptrauth keys at kernel exit time
    Date
    From: Mark Rutland <mark.rutland@arm.com>

    This will mean we do more work per EL0 exception return, but is a
    stepping-stone to enable keys within the kernel.

    Signed-off-by: Mark Rutland <mark.rutland@arm.com>
    Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>
    ---
    arch/arm64/include/asm/pointer_auth.h | 7 +------
    arch/arm64/include/asm/ptrauth-asm.h | 26 ++++++++++++++++++++++++++
    arch/arm64/kernel/asm-offsets.c | 7 +++++++
    arch/arm64/kernel/entry.S | 9 +++++++--
    arch/arm64/kernel/process.c | 1 -
    5 files changed, 41 insertions(+), 9 deletions(-)
    create mode 100644 arch/arm64/include/asm/ptrauth-asm.h

    diff --git a/arch/arm64/include/asm/pointer_auth.h b/arch/arm64/include/asm/pointer_auth.h
    index cedb03bd175b..5e40533f4ea2 100644
    --- a/arch/arm64/include/asm/pointer_auth.h
    +++ b/arch/arm64/include/asm/pointer_auth.h
    @@ -64,16 +64,11 @@ static inline unsigned long ptrauth_strip_insn_pac(unsigned long ptr)
    }

    #define ptrauth_task_init_user(tsk) \
    - ptrauth_keys_init(&(tsk)->thread_info.keys_user); \
    - ptrauth_keys_switch(&(tsk)->thread_info.keys_user)
    -
    -#define ptrauth_task_switch(tsk) \
    - ptrauth_keys_switch(&(tsk)->thread_info.keys_user)
    + ptrauth_keys_init(&(tsk)->thread_info.keys_user)

    #else /* CONFIG_ARM64_PTR_AUTH */
    #define ptrauth_strip_insn_pac(lr) (lr)
    #define ptrauth_task_init_user(tsk)
    -#define ptrauth_task_switch(tsk)
    #endif /* CONFIG_ARM64_PTR_AUTH */

    #endif /* __ASM_POINTER_AUTH_H */
    diff --git a/arch/arm64/include/asm/ptrauth-asm.h b/arch/arm64/include/asm/ptrauth-asm.h
    new file mode 100644
    index 000000000000..f50bdfc4046c
    --- /dev/null
    +++ b/arch/arm64/include/asm/ptrauth-asm.h
    @@ -0,0 +1,26 @@
    +/* SPDX-License-Identifier: GPL-2.0 */
    +#ifndef __ASM_PTRAUTH_ASM_H
    +#define __ASM_PTRAUTH_ASM_H
    +
    +#include <asm/asm-offsets.h>
    +#include <asm/sysreg.h>
    +
    +#ifdef CONFIG_ARM64_PTR_AUTH
    +
    + .macro ptrauth_keys_install_user tsk, tmp
    +alternative_if ARM64_HAS_ADDRESS_AUTH
    + ldr \tmp, [\tsk, #(TSK_TI_KEYS_USER + PTRAUTH_KEY_APIALO)]
    + msr_s SYS_APIAKEYLO_EL1, \tmp
    + ldr \tmp, [\tsk, #(TSK_TI_KEYS_USER + PTRAUTH_KEY_APIAHI)]
    + msr_s SYS_APIAKEYHI_EL1, \tmp
    +alternative_else_nop_endif
    + .endm
    +
    +#else /* CONFIG_ARM64_PTR_AUTH */
    +
    + .macro ptrauth_keys_install_user tsk, tmp
    + .endm
    +
    +#endif /* CONFIG_ARM64_PTR_AUTH */
    +
    +#endif /* __ASM_PTRAUTH_ASM_H */
    diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
    index 323aeb5f2fe6..b6be0dd037fd 100644
    --- a/arch/arm64/kernel/asm-offsets.c
    +++ b/arch/arm64/kernel/asm-offsets.c
    @@ -45,6 +45,9 @@ int main(void)
    #ifdef CONFIG_ARM64_SW_TTBR0_PAN
    DEFINE(TSK_TI_TTBR0, offsetof(struct task_struct, thread_info.ttbr0));
    #endif
    +#ifdef CONFIG_ARM64_PTR_AUTH
    + DEFINE(TSK_TI_KEYS_USER, offsetof(struct task_struct, thread_info.keys_user));
    +#endif
    DEFINE(TSK_STACK, offsetof(struct task_struct, stack));
    BLANK();
    DEFINE(THREAD_CPU_CONTEXT, offsetof(struct task_struct, thread.cpu_context));
    @@ -169,5 +172,9 @@ int main(void)
    DEFINE(SDEI_EVENT_INTREGS, offsetof(struct sdei_registered_event, interrupted_regs));
    DEFINE(SDEI_EVENT_PRIORITY, offsetof(struct sdei_registered_event, priority));
    #endif
    +#ifdef CONFIG_ARM64_PTR_AUTH
    + DEFINE(PTRAUTH_KEY_APIALO, offsetof(struct ptrauth_keys, apia.lo));
    + DEFINE(PTRAUTH_KEY_APIAHI, offsetof(struct ptrauth_keys, apia.hi));
    +#endif
    return 0;
    }
    diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
    index 09dbea221a27..1e925f6d2978 100644
    --- a/arch/arm64/kernel/entry.S
    +++ b/arch/arm64/kernel/entry.S
    @@ -23,8 +23,9 @@
    #include <linux/linkage.h>

    #include <asm/alternative.h>
    -#include <asm/assembler.h>
    #include <asm/asm-offsets.h>
    +#include <asm/asm-uaccess.h>
    +#include <asm/assembler.h>
    #include <asm/cpufeature.h>
    #include <asm/errno.h>
    #include <asm/esr.h>
    @@ -33,8 +34,8 @@
    #include <asm/mmu.h>
    #include <asm/processor.h>
    #include <asm/ptrace.h>
    +#include <asm/ptrauth-asm.h>
    #include <asm/thread_info.h>
    -#include <asm/asm-uaccess.h>
    #include <asm/unistd.h>

    /*
    @@ -325,6 +326,10 @@ alternative_else_nop_endif
    apply_ssbd 0, x0, x1
    .endif

    + .if \el == 0
    + ptrauth_keys_install_user tsk, x0
    + .endif
    +
    msr elr_el1, x21 // set up the return data
    msr spsr_el1, x22
    ldp x0, x1, [sp, #16 * 0]
    diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
    index fae52be66c92..857ae05cd04c 100644
    --- a/arch/arm64/kernel/process.c
    +++ b/arch/arm64/kernel/process.c
    @@ -426,7 +426,6 @@ __notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev,
    contextidr_thread_switch(next);
    entry_task_switch(next);
    uao_thread_switch(next);
    - ptrauth_task_switch(next);

    /*
    * Complete any pending TLB or cache maintenance on this CPU in case
    --
    2.11.0
    \
     
     \ /
      Last update: 2018-10-05 10:51    [W:2.068 / U:0.216 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site