From: Suzuki K Poulose <suzuki.poulose@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org, catalin.marinas@arm.com,
mark.rutland@arm.com, will.deacon@arm.com, marc.zyngier@arm.com,
Suzuki K Poulose <suzuki.poulose@arm.com>
Subject: [PATCH 2/3] arm64: Add assembly helpers for MIDR range check
Date: Tue, 16 Jan 2018 10:23:22 +0000 [thread overview]
Message-ID: <20180116102323.3470-3-suzuki.poulose@arm.com> (raw)
In-Reply-To: <20180116102323.3470-1-suzuki.poulose@arm.com>
Add a helper to check the MIDR of the running CPU against a given
MODEL and a range of revision and variants (just like we do in
is_affected_midr_range()). This will be useful for early checks
for MIDR to detect CPU errata.
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
arch/arm64/include/asm/assembler.h | 40 ++++++++++++++++++++++++++++++++++++++
1 file changed, 40 insertions(+)
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 5dc4856f3bb9..596b693edb2c 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -25,6 +25,7 @@
#include <asm/asm-offsets.h>
#include <asm/cpufeature.h>
+#include <asm/cputype.h>
#include <asm/debug-monitors.h>
#include <asm/page.h>
#include <asm/pgtable-hwdef.h>
@@ -516,4 +517,43 @@ alternative_endif
#endif
.endm
+/*
+ * Check the MIDR_EL1 of the current CPU for a given model and a range of
+ * variant/revision. See asm/cputype.h for the macros used below.
+ *
+ * model: MIDR_CPU_MODEL of CPU
+ * rv_min: Minimum of MIDR_CPU_VAR_REV()
+ * rv_max: Maximum of MIDR_CPU_VAR_REV()
+ * res: Result register.
+ * tmp1, tmp2, tmp3: Temporary registers
+ *
+ * Corrupts: res, tmp1, tmp2, tmp3
+ * Returns: 0, if the CPU id doesn't match. Non-zero otherwise
+ */
+ .macro cpu_midr_match model, rv_min, rv_max, res, tmp1, tmp2, tmp3
+ mrs \res, midr_el1
+ mov_q \tmp1, (MIDR_REVISION_MASK | MIDR_VARIANT_MASK)
+ mov_q \tmp2, MIDR_CPU_MODEL_MASK
+ and \tmp3, \res, \tmp2 // Extract model
+ and \tmp1, \res, \tmp1 // rev & variant
+ mov_q \tmp2, \model
+ cmp \tmp3, \tmp2
+ cset \res, eq
+ cbz \res, .Ldone\@ // Model matches ?
+
+ .if (\rv_min != 0) // Skip min check if rv_min == 0
+ mov_q \tmp3, \rv_min
+ cmp \tmp1, \tmp3
+ cset \res, ge
+ .endif // \rv_min != 0
+ /* Skip rv_max check if rv_min == rv_max && rv_min != 0 */
+ .if ((\rv_min != \rv_max) || \rv_min == 0)
+ mov_q \tmp2, \rv_max
+ cmp \tmp1, \tmp2
+ cset \tmp2, le
+ and \res, \res, \tmp2
+ .endif
+.Ldone\@:
+ .endm
+
#endif /* __ASM_ASSEMBLER_H */
--
2.13.6
next prev parent reply other threads:[~2018-01-16 10:24 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-16 10:23 [PATCH 0/3] arm64: Enable work around for Cortex-A55 erratum 1024718 Suzuki K Poulose
2018-01-16 10:23 ` [PATCH 1/3] arm64: Update MIDR definitions for Arm Cortex-A cores Suzuki K Poulose
2018-01-16 10:23 ` Suzuki K Poulose [this message]
2018-01-16 10:23 ` [PATCH 3/3] arm64: Add work around for Arm Cortex-A55 Erratum 1024718 Suzuki K Poulose
2018-01-17 3:34 ` ckadabi
2018-01-17 10:28 ` Suzuki K Poulose
2018-01-18 5:00 ` Channa
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180116102323.3470-3-suzuki.poulose@arm.com \
--to=suzuki.poulose@arm.com \
--cc=catalin.marinas@arm.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=marc.zyngier@arm.com \
--cc=mark.rutland@arm.com \
--cc=will.deacon@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).