From: Kees Cook <keescook@chromium.org>
To: Mark Brown <broonie@kernel.org>
Cc: "Catalin Marinas" <catalin.marinas@arm.com>,
"Will Deacon" <will@kernel.org>,
"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>,
"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>
Subject: Re: [PATCH v7 06/11] arm64: BTI: Decode BYTPE bits when printing PSTATE
Date: Wed, 26 Feb 2020 13:42:01 -0800 [thread overview]
Message-ID: <202002261341.D2BB57A@keescook> (raw)
In-Reply-To: <20200226155714.43937-7-broonie@kernel.org>
On Wed, Feb 26, 2020 at 03:57:09PM +0000, Mark Brown wrote:
> 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>
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
> 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
>
--
Kees Cook
next prev parent reply other threads:[~2020-02-26 21:42 UTC|newest]
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 ` [PATCH v7 06/11] arm64: BTI: Decode BYTPE bits when printing PSTATE Mark Brown
2020-02-26 21:42 ` Kees Cook [this message]
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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