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From:   gregkh@linuxfoundation.org
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Nicholas Piggin <npiggin@gmail.com>,
        Michael Ellerman <mpe@ellerman.id.au>
Subject: [PATCH 5.11 281/306] powerpc: Fix inverted SET_FULL_REGS bitop
Date:   Mon, 15 Mar 2021 14:55:44 +0100
Message-Id: <20210315135517.178753846@linuxfoundation.org>
In-Reply-To: <20210315135507.611436477@linuxfoundation.org>
References: <20210315135507.611436477@linuxfoundation.org>
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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

From: Nicholas Piggin <npiggin@gmail.com>

commit 73ac79881804eed2e9d76ecdd1018037f8510cb1 upstream.

This bit operation was inverted and set the low bit rather than
cleared it, breaking the ability to ptrace non-volatile GPRs after
exec. Fix.

Only affects 64e and 32-bit.

Fixes: feb9df3462e6 ("powerpc/64s: Always has full regs, so remove remnant checks")
Cc: stable@vger.kernel.org # v5.8+
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210308085530.3191843-1-npiggin@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/powerpc/include/asm/ptrace.h |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/powerpc/include/asm/ptrace.h
+++ b/arch/powerpc/include/asm/ptrace.h
@@ -195,7 +195,7 @@ static inline void regs_set_return_value
 #define TRAP_FLAGS_MASK		0x11
 #define TRAP(regs)		((regs)->trap & ~TRAP_FLAGS_MASK)
 #define FULL_REGS(regs)		(((regs)->trap & 1) == 0)
-#define SET_FULL_REGS(regs)	((regs)->trap |= 1)
+#define SET_FULL_REGS(regs)	((regs)->trap &= ~1)
 #endif
 #define CHECK_FULL_REGS(regs)	BUG_ON(!FULL_REGS(regs))
 #define NV_REG_POISON		0xdeadbeefdeadbeefUL
@@ -210,7 +210,7 @@ static inline void regs_set_return_value
 #define TRAP_FLAGS_MASK		0x1F
 #define TRAP(regs)		((regs)->trap & ~TRAP_FLAGS_MASK)
 #define FULL_REGS(regs)		(((regs)->trap & 1) == 0)
-#define SET_FULL_REGS(regs)	((regs)->trap |= 1)
+#define SET_FULL_REGS(regs)	((regs)->trap &= ~1)
 #define IS_CRITICAL_EXC(regs)	(((regs)->trap & 2) != 0)
 #define IS_MCHECK_EXC(regs)	(((regs)->trap & 4) != 0)
 #define IS_DEBUG_EXC(regs)	(((regs)->trap & 8) != 0)