From c5cc1f4df6b16646f8fae7aab523c1820bf916e8 Mon Sep 17 00:00:00 2001 From: Thiago Jung Bauermann Date: Thu, 18 Jan 2018 17:50:43 -0800 Subject: powerpc/ptrace: Add memory protection key regset The AMR/IAMR/UAMOR are part of the program context. Allow it to be accessed via ptrace and through core files. Signed-off-by: Ram Pai Signed-off-by: Thiago Jung Bauermann Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/pkeys.h | 5 +++ arch/powerpc/include/uapi/asm/elf.h | 1 + arch/powerpc/kernel/ptrace.c | 66 +++++++++++++++++++++++++++++++++++++ arch/powerpc/kernel/traps.c | 7 ++++ 4 files changed, 79 insertions(+) (limited to 'arch/powerpc') diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h index 2298771b066b..c3cbad824e5a 100644 --- a/arch/powerpc/include/asm/pkeys.h +++ b/arch/powerpc/include/asm/pkeys.h @@ -202,6 +202,11 @@ static inline int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, return __arch_set_user_pkey_access(tsk, pkey, init_val); } +static inline bool arch_pkeys_enabled(void) +{ + return !static_branch_likely(&pkey_disabled); +} + extern void pkey_mm_init(struct mm_struct *mm); extern void thread_pkey_regs_save(struct thread_struct *thread); extern void thread_pkey_regs_restore(struct thread_struct *new_thread, diff --git a/arch/powerpc/include/uapi/asm/elf.h b/arch/powerpc/include/uapi/asm/elf.h index 5f201d40bcca..860c59291bfc 100644 --- a/arch/powerpc/include/uapi/asm/elf.h +++ b/arch/powerpc/include/uapi/asm/elf.h @@ -97,6 +97,7 @@ #define ELF_NTMSPRREG 3 /* include tfhar, tfiar, texasr */ #define ELF_NEBB 3 /* includes ebbrr, ebbhr, bescr */ #define ELF_NPMU 5 /* includes siar, sdar, sier, mmcr2, mmcr0 */ +#define ELF_NPKEY 3 /* includes amr, iamr, uamor */ typedef unsigned long elf_greg_t64; typedef elf_greg_t64 elf_gregset_t64[ELF_NGREG]; diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c index aef08e579946..ca72d7391d40 100644 --- a/arch/powerpc/kernel/ptrace.c +++ b/arch/powerpc/kernel/ptrace.c @@ -35,6 +35,7 @@ #include #include +#include #include #include #include @@ -1787,6 +1788,61 @@ static int pmu_set(struct task_struct *target, return ret; } #endif + +#ifdef CONFIG_PPC_MEM_KEYS +static int pkey_active(struct task_struct *target, + const struct user_regset *regset) +{ + if (!arch_pkeys_enabled()) + return -ENODEV; + + return regset->n; +} + +static int pkey_get(struct task_struct *target, + const struct user_regset *regset, + unsigned int pos, unsigned int count, + void *kbuf, void __user *ubuf) +{ + 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)); +} + +static int pkey_set(struct task_struct *target, + const struct user_regset *regset, + unsigned int pos, unsigned int count, + const void *kbuf, const void __user *ubuf) +{ + u64 new_amr; + int ret; + + if (!arch_pkeys_enabled()) + return -ENODEV; + + /* Only the AMR can be set from userspace */ + if (pos != 0 || count != sizeof(new_amr)) + return -EINVAL; + + ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, + &new_amr, 0, sizeof(new_amr)); + if (ret) + 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); + + return 0; +} +#endif /* CONFIG_PPC_MEM_KEYS */ + /* * These are our native regset flavors. */ @@ -1821,6 +1877,9 @@ enum powerpc_regset { REGSET_EBB, /* EBB registers */ REGSET_PMR, /* Performance Monitor Registers */ #endif +#ifdef CONFIG_PPC_MEM_KEYS + REGSET_PKEY, /* AMR register */ +#endif }; static const struct user_regset native_regsets[] = { @@ -1926,6 +1985,13 @@ static const struct user_regset native_regsets[] = { .active = pmu_active, .get = pmu_get, .set = pmu_set }, #endif +#ifdef CONFIG_PPC_MEM_KEYS + [REGSET_PKEY] = { + .core_note_type = NT_PPC_PKEY, .n = ELF_NPKEY, + .size = sizeof(u64), .align = sizeof(u64), + .active = pkey_active, .get = pkey_get, .set = pkey_set + }, +#endif }; static const struct user_regset_view user_ppc_native_view = { diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index 4b1a8e2ec023..122a3c883f4e 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -292,6 +292,13 @@ void _exception_pkey(int signr, struct pt_regs *regs, int code, local_irq_enable(); 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); + memset(&info, 0, sizeof(info)); info.si_signo = signr; info.si_code = code; -- cgit v1.2.3