Add PKEY support to signals, by saving and restoring POR_EL0 from the stackframe.
Signed-off-by: Joey Gouly joey.gouly@arm.com Cc: Catalin Marinas catalin.marinas@arm.com Cc: Will Deacon will@kernel.org Reviewed-by: Mark Brown broonie@kernel.org --- arch/arm64/include/uapi/asm/sigcontext.h | 7 ++++ arch/arm64/kernel/signal.c | 51 ++++++++++++++++++++++++ 2 files changed, 58 insertions(+)
diff --git a/arch/arm64/include/uapi/asm/sigcontext.h b/arch/arm64/include/uapi/asm/sigcontext.h index f23c1dc3f002..cef85eeaf541 100644 --- a/arch/arm64/include/uapi/asm/sigcontext.h +++ b/arch/arm64/include/uapi/asm/sigcontext.h @@ -98,6 +98,13 @@ struct esr_context { __u64 esr; };
+#define POE_MAGIC 0x504f4530 + +struct poe_context { + struct _aarch64_ctx head; + __u64 por_el0; +}; + /* * extra_context: describes extra space in the signal frame for * additional structures that don't fit in sigcontext.__reserved[]. diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 0e8beb3349ea..379f364005bf 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -62,6 +62,7 @@ struct rt_sigframe_user_layout { unsigned long zt_offset; unsigned long extra_offset; unsigned long end_offset; + unsigned long poe_offset; };
#define BASE_SIGFRAME_SIZE round_up(sizeof(struct rt_sigframe), 16) @@ -182,6 +183,8 @@ struct user_ctxs { u32 za_size; struct zt_context __user *zt; u32 zt_size; + struct poe_context __user *poe; + u32 poe_size; };
static int preserve_fpsimd_context(struct fpsimd_context __user *ctx) @@ -227,6 +230,20 @@ static int restore_fpsimd_context(struct user_ctxs *user) return err ? -EFAULT : 0; }
+static int restore_poe_context(struct user_ctxs *user) +{ + u64 por_el0; + int err = 0; + + if (user->poe_size != sizeof(*user->poe)) + return -EINVAL; + + __get_user_error(por_el0, &(user->poe->por_el0), err); + if (!err) + write_sysreg_s(por_el0, SYS_POR_EL0); + + return err; +}
#ifdef CONFIG_ARM64_SVE
@@ -590,6 +607,7 @@ static int parse_user_sigframe(struct user_ctxs *user, user->tpidr2 = NULL; user->za = NULL; user->zt = NULL; + user->poe = NULL;
if (!IS_ALIGNED((unsigned long)base, 16)) goto invalid; @@ -640,6 +658,17 @@ static int parse_user_sigframe(struct user_ctxs *user, /* ignore */ break;
+ case POE_MAGIC: + if (!system_supports_poe()) + goto invalid; + + if (user->poe) + goto invalid; + + user->poe = (struct poe_context __user *)head; + user->poe_size = size; + break; + case SVE_MAGIC: if (!system_supports_sve() && !system_supports_sme()) goto invalid; @@ -812,6 +841,9 @@ static int restore_sigframe(struct pt_regs *regs, if (err == 0 && system_supports_sme2() && user.zt) err = restore_zt_context(&user);
+ if (err == 0 && system_supports_poe() && user.poe) + err = restore_poe_context(&user); + return err; }
@@ -928,6 +960,13 @@ static int setup_sigframe_layout(struct rt_sigframe_user_layout *user, } }
+ if (system_supports_poe()) { + err = sigframe_alloc(user, &user->poe_offset, + sizeof(struct poe_context)); + if (err) + return err; + } + return sigframe_alloc_end(user); }
@@ -968,6 +1007,15 @@ static int setup_sigframe(struct rt_sigframe_user_layout *user, __put_user_error(current->thread.fault_code, &esr_ctx->esr, err); }
+ if (system_supports_poe() && err == 0 && user->poe_offset) { + struct poe_context __user *poe_ctx = + apply_user_offset(user, user->poe_offset); + + __put_user_error(POE_MAGIC, &poe_ctx->head.magic, err); + __put_user_error(sizeof(*poe_ctx), &poe_ctx->head.size, err); + __put_user_error(read_sysreg_s(SYS_POR_EL0), &poe_ctx->por_el0, err); + } + /* Scalable Vector Extension state (including streaming), if present */ if ((system_supports_sve() || system_supports_sme()) && err == 0 && user->sve_offset) { @@ -1119,6 +1167,9 @@ static void setup_return(struct pt_regs *regs, struct k_sigaction *ka, sme_smstop(); }
+ if (system_supports_poe()) + write_sysreg_s(POR_EL0_INIT, SYS_POR_EL0); + if (ka->sa.sa_flags & SA_RESTORER) sigtramp = ka->sa.sa_restorer; else