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From: Mark Brown <broonie@kernel.org>
To: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>
Cc: "Alexander Viro" <viro@zeniv.linux.org.uk>,
	"Paul Elliott" <paul.elliott@arm.com>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Yu-cheng Yu" <yu-cheng.yu@intel.com>,
	"Amit Kachhap" <amit.kachhap@arm.com>,
	"Vincenzo Frascino" <vincenzo.frascino@arm.com>,
	"Marc Zyngier" <maz@kernel.org>,
	"Eugene Syromiatnikov" <esyr@redhat.com>,
	"Szabolcs Nagy" <szabolcs.nagy@arm.com>,
	"H . J . Lu " <hjl.tools@gmail.com>,
	"Andrew Jones" <drjones@redhat.com>,
	"Kees Cook" <keescook@chromium.org>,
	"Arnd Bergmann" <arnd@arndb.de>, "Jann Horn" <jannh@google.com>,
	"Richard Henderson" <richard.henderson@linaro.org>,
	"Kristina Martšenko" <kristina.martsenko@arm.com>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Florian Weimer" <fweimer@redhat.com>,
	"Sudakshina Das" <sudi.das@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
	linux-fsdevel@vger.kernel.org,
	"Dave Martin" <Dave.Martin@arm.com>,
	"Mark Brown" <broonie@kernel.org>
Subject: [PATCH v7 06/11] arm64: BTI: Decode BYTPE bits when printing PSTATE
Date: Wed, 26 Feb 2020 15:57:09 +0000
Message-ID: <20200226155714.43937-7-broonie@kernel.org> (raw)
In-Reply-To: <20200226155714.43937-1-broonie@kernel.org>

From: Dave Martin <Dave.Martin@arm.com>

The current code to print PSTATE symbolically when generating
backtraces etc., does not include the BYTPE field used by Branch
Target Identification.

So, decode BYTPE and print it too.

In the interests of human-readability, print the classes of BTI
matched.  The symbolic notation, BYTPE (PSTATE[11:10]) and
permitted classes of subsequent instruction are:

    -- (BTYPE=0b00): any insn
    jc (BTYPE=0b01): BTI jc, BTI j, BTI c, PACIxSP
    -c (BYTPE=0b10): BTI jc, BTI c, PACIxSP
    j- (BTYPE=0b11): BTI jc, BTI j

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/kernel/process.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index b8e3faa8d406..24af13d7bde6 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -211,6 +211,15 @@ void machine_restart(char *cmd)
 	while (1);
 }
 
+#define bstr(suffix, str) [PSR_BTYPE_ ## suffix >> PSR_BTYPE_SHIFT] = str
+static const char *const btypes[] = {
+	bstr(NONE, "--"),
+	bstr(  JC, "jc"),
+	bstr(   C, "-c"),
+	bstr(  J , "j-")
+};
+#undef bstr
+
 static void print_pstate(struct pt_regs *regs)
 {
 	u64 pstate = regs->pstate;
@@ -229,7 +238,10 @@ static void print_pstate(struct pt_regs *regs)
 			pstate & PSR_AA32_I_BIT ? 'I' : 'i',
 			pstate & PSR_AA32_F_BIT ? 'F' : 'f');
 	} else {
-		printk("pstate: %08llx (%c%c%c%c %c%c%c%c %cPAN %cUAO)\n",
+		const char *btype_str = btypes[(pstate & PSR_BTYPE_MASK) >>
+					       PSR_BTYPE_SHIFT];
+
+		printk("pstate: %08llx (%c%c%c%c %c%c%c%c %cPAN %cUAO BTYPE=%s)\n",
 			pstate,
 			pstate & PSR_N_BIT ? 'N' : 'n',
 			pstate & PSR_Z_BIT ? 'Z' : 'z',
@@ -240,7 +252,8 @@ static void print_pstate(struct pt_regs *regs)
 			pstate & PSR_I_BIT ? 'I' : 'i',
 			pstate & PSR_F_BIT ? 'F' : 'f',
 			pstate & PSR_PAN_BIT ? '+' : '-',
-			pstate & PSR_UAO_BIT ? '+' : '-');
+			pstate & PSR_UAO_BIT ? '+' : '-',
+			btype_str);
 	}
 }
 
-- 
2.20.1


  parent reply index

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-26 15:57 [PATCH v7 00/11] arm64: Branch Target Identification support Mark Brown
2020-02-26 15:57 ` [PATCH v7 01/11] ELF: UAPI and Kconfig additions for ELF program properties Mark Brown
2020-02-26 15:57 ` [PATCH v7 02/11] ELF: Add ELF program property parsing support Mark Brown
2020-02-26 15:57 ` [PATCH v7 03/11] arm64: Basic Branch Target Identification support Mark Brown
2020-02-26 15:57 ` [PATCH v7 04/11] elf: Allow arch to tweak initial mmap prot flags Mark Brown
2020-02-26 15:57 ` [PATCH v7 05/11] arm64: elf: Enable BTI at exec based on ELF program properties Mark Brown
2020-02-26 21:43   ` Kees Cook
2020-02-27  4:45   ` Amit Kachhap
2020-02-26 15:57 ` Mark Brown [this message]
2020-02-26 21:42   ` [PATCH v7 06/11] arm64: BTI: Decode BYTPE bits when printing PSTATE Kees Cook
2020-02-26 15:57 ` [PATCH v7 07/11] arm64: unify native/compat instruction skipping Mark Brown
2020-02-26 21:41   ` Kees Cook
2020-02-26 15:57 ` [PATCH v7 08/11] arm64: traps: Shuffle code to eliminate forward declarations Mark Brown
2020-02-26 21:39   ` Kees Cook
2020-02-26 15:57 ` [PATCH v7 09/11] arm64: BTI: Reset BTYPE when skipping emulated instructions Mark Brown
2020-02-26 15:57 ` [PATCH v7 10/11] KVM: " Mark Brown
2020-02-26 15:57 ` [PATCH v7 11/11] arm64: mm: Display guarded pages in ptdump Mark Brown
2020-02-26 21:38   ` Kees Cook
2020-02-26 21:44 ` [PATCH v7 00/11] arm64: Branch Target Identification support Kees Cook
2020-02-27 13:13   ` Mark Brown

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