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 Acked-by: Szabolcs Nagy szabolcs.nagy@arm.com Reviewed-by: Catalin Marinas catalin.marinas@arm.com Reviewed-by: Anshuman Khandual anshuman.khandual@arm.com --- arch/arm64/include/uapi/asm/sigcontext.h | 7 +++ arch/arm64/kernel/signal.c | 62 ++++++++++++++++++++++++ 2 files changed, 69 insertions(+)
diff --git arch/arm64/include/uapi/asm/sigcontext.h arch/arm64/include/uapi/asm/sigcontext.h index 8a45b7a411e0..e4cba8a6c9a2 100644 --- arch/arm64/include/uapi/asm/sigcontext.h +++ 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 arch/arm64/kernel/signal.c arch/arm64/kernel/signal.c index 4a77f4976e11..561986947530 100644 --- arch/arm64/kernel/signal.c +++ arch/arm64/kernel/signal.c @@ -61,6 +61,7 @@ struct rt_sigframe_user_layout { unsigned long za_offset; unsigned long zt_offset; unsigned long fpmr_offset; + unsigned long poe_offset; unsigned long extra_offset; unsigned long end_offset; }; @@ -185,6 +186,8 @@ struct user_ctxs { u32 zt_size; struct fpmr_context __user *fpmr; u32 fpmr_size; + struct poe_context __user *poe; + u32 poe_size; };
static int preserve_fpsimd_context(struct fpsimd_context __user *ctx) @@ -258,6 +261,32 @@ static int restore_fpmr_context(struct user_ctxs *user) return err; }
+static int preserve_poe_context(struct poe_context __user *ctx) +{ + int err = 0; + + __put_user_error(POE_MAGIC, &ctx->head.magic, err); + __put_user_error(sizeof(*ctx), &ctx->head.size, err); + __put_user_error(read_sysreg_s(SYS_POR_EL0), &ctx->por_el0, err); + + return err; +} + +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
static int preserve_sve_context(struct sve_context __user *ctx) @@ -621,6 +650,7 @@ static int parse_user_sigframe(struct user_ctxs *user, user->za = NULL; user->zt = NULL; user->fpmr = NULL; + user->poe = NULL;
if (!IS_ALIGNED((unsigned long)base, 16)) goto invalid; @@ -671,6 +701,17 @@ 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; @@ -857,6 +898,9 @@ 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; }
@@ -980,6 +1024,13 @@ static int setup_sigframe_layout(struct rt_sigframe_user_layout *user, return err; }
+ if (system_supports_poe()) { + err = sigframe_alloc(user, &user->poe_offset, + sizeof(struct poe_context)); + if (err) + return err; + } + return sigframe_alloc_end(user); }
@@ -1042,6 +1093,14 @@ static int setup_sigframe(struct rt_sigframe_user_layout *user, err |= preserve_fpmr_context(fpmr_ctx); }
+ if (system_supports_poe() && err == 0 && user->poe_offset) { + struct poe_context __user *poe_ctx = + apply_user_offset(user, user->poe_offset); + + err |= preserve_poe_context(poe_ctx); + } + + /* ZA state if present */ if (system_supports_sme() && err == 0 && user->za_offset) { struct za_context __user *za_ctx = @@ -1178,6 +1237,9 @@ 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