All of lore.kernel.org
 help / color / mirror / Atom feed
From: Srinivas Ramana <sramana@codeaurora.org>
To: catalin.marinas@arm.com, will@kernel.org, pajay@qti.qualcomm.com
Cc: linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-arm-msm@vger.kernel.org,
	Srinivas Ramana <sramana@codeaurora.org>,
	Prasad Sodagudi <psodagud@codeaurora.org>
Subject: [PATCH 3/3] arm64: Enable control of pointer authentication using early param
Date: Fri,  8 Jan 2021 16:29:23 -0800	[thread overview]
Message-ID: <1610152163-16554-4-git-send-email-sramana@codeaurora.org> (raw)
In-Reply-To: <1610152163-16554-1-git-send-email-sramana@codeaurora.org>

Add support to control turning off the pointer authentication
using a kernel command line early param.
This will help control pointer authentication feature for both kernel
and userspace without kernel changes.

Signed-off-by: Ajay Patil <pajay@qti.qualcomm.com>
Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>
Signed-off-by: Srinivas Ramana <sramana@codeaurora.org>
---
 Documentation/admin-guide/kernel-parameters.txt |  6 ++++
 arch/arm64/kernel/cpufeature.c                  | 38 +++++++++++++++++++------
 2 files changed, 36 insertions(+), 8 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index c722ec19cd00..d6855e0a9085 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -373,6 +373,12 @@
 	arcrimi=	[HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
 			Format: <io>,<irq>,<nodeID>
 
+	arm64.disable_ptr_auth=
+			[ARM64] Force disable Linux support for address
+			authentication (both user and in-kernel).
+			0 - Pointer authentication is enabled[Default]
+			1 - Pointer authentication is force disabled
+
 	ataflop=	[HW,M68k]
 
 	atarimouse=	[HW,MOUSE] Atari Mouse
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index b2ffa9eaaaff..bdaaff78240b 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -164,6 +164,24 @@ static void cpu_enable_cnp(struct arm64_cpu_capabilities const *cap);
 
 static bool __system_matches_cap(unsigned int n);
 
+#ifdef CONFIG_ARM64_PTR_AUTH
+bool arm64_disable_ptr_auth;
+
+static int __init arm64_disable_ptr_auth_fn(char *buf)
+{
+	return strtobool(buf, &arm64_disable_ptr_auth);
+}
+early_param("arm64.disable_ptr_auth", arm64_disable_ptr_auth_fn);
+
+s64 ptr_auth_ftr_filter(const struct arm64_ftr_bits *ftrp, s64 val)
+{
+	if (arm64_disable_ptr_auth)
+		return 0;
+	else
+		return val;
+}
+#endif
+
 /*
  * NOTE: Any changes to the visibility of features should be kept in
  * sync with the documentation of the CPU feature register ABI.
@@ -193,17 +211,21 @@ static const struct arm64_ftr_bits ftr_id_aa64isar1[] = {
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_SPECRES_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_SB_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_FRINTTS_SHIFT, 4, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_PTR_AUTH),
-		       FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_GPI_SHIFT, 4, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_PTR_AUTH),
-		       FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_GPA_SHIFT, 4, 0),
+#ifdef CONFIG_ARM64_PTR_AUTH
+	FILTERED_ARM64_FTR_BITS(FTR_UNSIGNED, FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE,
+				ID_AA64ISAR1_GPI_SHIFT, 4, 0, ptr_auth_ftr_filter),
+	FILTERED_ARM64_FTR_BITS(FTR_UNSIGNED, FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE,
+				ID_AA64ISAR1_GPA_SHIFT, 4, 0, ptr_auth_ftr_filter),
+#endif
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_LRCPC_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_FCMA_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_JSCVT_SHIFT, 4, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_PTR_AUTH),
-		       FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_API_SHIFT, 4, 0),
-	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_PTR_AUTH),
-		       FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_APA_SHIFT, 4, 0),
+#ifdef CONFIG_ARM64_PTR_AUTH
+	FILTERED_ARM64_FTR_BITS(FTR_UNSIGNED, FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE,
+				ID_AA64ISAR1_API_SHIFT, 4, 0, ptr_auth_ftr_filter),
+	FILTERED_ARM64_FTR_BITS(FTR_UNSIGNED, FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE,
+				ID_AA64ISAR1_APA_SHIFT, 4, 0, ptr_auth_ftr_filter),
+#endif
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_DPB_SHIFT, 4, 0),
 	ARM64_FTR_END,
 };
-- 
2.7.4


  parent reply	other threads:[~2021-01-09  0:31 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-09  0:29 [PATCH 0/3] arm64: cpufeature: Add filter function to control Srinivas Ramana
2021-01-09  0:29 ` [PATCH 1/3] arm64: Defer enabling pointer authentication on boot core Srinivas Ramana
2021-01-09  0:29 ` [PATCH 2/3] arm64: cpufeature: Add a filter function to cpufeature Srinivas Ramana
2021-01-09  0:29 ` Srinivas Ramana [this message]
2021-01-11 13:40 ` [PATCH 0/3] arm64: cpufeature: Add filter function to control Marc Zyngier
2021-01-11 13:40   ` Marc Zyngier
2021-01-14  7:15   ` Srinivas Ramana
2021-01-14  8:20     ` Marc Zyngier
2021-01-14  8:20       ` Marc Zyngier
2021-01-14 18:37       ` Catalin Marinas
2021-01-14 18:37         ` Catalin Marinas

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=1610152163-16554-4-git-send-email-sramana@codeaurora.org \
    --to=sramana@codeaurora.org \
    --cc=catalin.marinas@arm.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-arm-msm@vger.kernel.org \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=pajay@qti.qualcomm.com \
    --cc=psodagud@codeaurora.org \
    --cc=will@kernel.org \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.