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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Mark Rutland <mark.rutland@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Suzuki Poulose <suzuki.poulose@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Guenter Roeck <linux@roeck-us.net>
Subject: [PATCH 4.14 086/148] arm64: compat: map SPSR_ELx<->PSR for signals
Date:   Wed,  1 Apr 2020 18:17:58 +0200
Message-Id: <20200401161601.333675944@linuxfoundation.org>
In-Reply-To: <20200401161552.245876366@linuxfoundation.org>
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From: Mark Rutland <mark.rutland@arm.com>

commit 25dc2c80cfa33153057aa94984855acd57adf92a upstream.

The SPSR_ELx format for exceptions taken from AArch32 differs from the
AArch32 PSR format. Thus, we must translate between the two when setting
up a compat sigframe, or restoring context from a compat sigframe.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Fixes: 7206dc93a58fb764 ("arm64: Expose Arm v8.4 features")
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Suzuki Poulose <suzuki.poulose@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/arm64/kernel/signal32.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/arch/arm64/kernel/signal32.c
+++ b/arch/arm64/kernel/signal32.c
@@ -321,6 +321,7 @@ static int compat_restore_sigframe(struc
 	int err;
 	sigset_t set;
 	struct compat_aux_sigframe __user *aux;
+	unsigned long psr;
 
 	err = get_sigset_t(&set, &sf->uc.uc_sigmask);
 	if (err == 0) {
@@ -344,7 +345,9 @@ static int compat_restore_sigframe(struc
 	__get_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err);
 	__get_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err);
 	__get_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err);
-	__get_user_error(regs->pstate, &sf->uc.uc_mcontext.arm_cpsr, err);
+	__get_user_error(psr, &sf->uc.uc_mcontext.arm_cpsr, err);
+
+	regs->pstate = compat_psr_to_pstate(psr);
 
 	/*
 	 * Avoid compat_sys_sigreturn() restarting.
@@ -500,6 +503,7 @@ static int compat_setup_sigframe(struct
 				 struct pt_regs *regs, sigset_t *set)
 {
 	struct compat_aux_sigframe __user *aux;
+	unsigned long psr = pstate_to_compat_psr(regs->pstate);
 	int err = 0;
 
 	__put_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err);
@@ -518,7 +522,7 @@ static int compat_setup_sigframe(struct
 	__put_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err);
 	__put_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err);
 	__put_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err);
-	__put_user_error(regs->pstate, &sf->uc.uc_mcontext.arm_cpsr, err);
+	__put_user_error(psr, &sf->uc.uc_mcontext.arm_cpsr, err);
 
 	__put_user_error((compat_ulong_t)0, &sf->uc.uc_mcontext.trap_no, err);
 	/* set the compat FSR WnR */