linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Nathan Chancellor <natechancellor@gmail.com>
To: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Florian Fainelli <f.fainelli@gmail.com>,
	John Crispin <john@phrozen.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	bcm-kernel-feedback-list@broadcom.com,
	linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
	clang-built-linux@googlegroups.com,
	Nathan Chancellor <natechancellor@gmail.com>
Subject: [PATCH] MIPS: Use address-of operator on section symbols
Date: Tue,  5 Jan 2021 13:18:27 -0700	[thread overview]
Message-ID: <20210105201827.51766-1-natechancellor@gmail.com> (raw)

When building xway_defconfig with clang:

arch/mips/lantiq/prom.c:82:23: error: array comparison always evaluates
to true [-Werror,-Wtautological-compare]
        else if (__dtb_start != __dtb_end)
                             ^
1 error generated.

These are not true arrays, they are linker defined symbols, which are
just addresses. Using the address of operator silences the warning
and does not change the resulting assembly with either clang/ld.lld
or gcc/ld (tested with diff + objdump -Dr). Do the same thing across
the entire MIPS subsystem to ensure there are no more warnings around
this type of comparison.

Link: https://github.com/ClangBuiltLinux/linux/issues/1232
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---
 arch/mips/bmips/setup.c          | 2 +-
 arch/mips/lantiq/prom.c          | 2 +-
 arch/mips/pic32/pic32mzda/init.c | 2 +-
 arch/mips/ralink/of.c            | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/mips/bmips/setup.c b/arch/mips/bmips/setup.c
index 19308df5f577..1b06b25aea87 100644
--- a/arch/mips/bmips/setup.c
+++ b/arch/mips/bmips/setup.c
@@ -167,7 +167,7 @@ void __init plat_mem_setup(void)
 		dtb = phys_to_virt(fw_arg2);
 	else if (fw_passed_dtb) /* UHI interface or appended dtb */
 		dtb = (void *)fw_passed_dtb;
-	else if (__dtb_start != __dtb_end)
+	else if (&__dtb_start != &__dtb_end)
 		dtb = (void *)__dtb_start;
 	else
 		panic("no dtb found");
diff --git a/arch/mips/lantiq/prom.c b/arch/mips/lantiq/prom.c
index 51a218f04fe0..3f568f5aae2d 100644
--- a/arch/mips/lantiq/prom.c
+++ b/arch/mips/lantiq/prom.c
@@ -79,7 +79,7 @@ void __init plat_mem_setup(void)
 
 	if (fw_passed_dtb) /* UHI interface */
 		dtb = (void *)fw_passed_dtb;
-	else if (__dtb_start != __dtb_end)
+	else if (&__dtb_start != &__dtb_end)
 		dtb = (void *)__dtb_start;
 	else
 		panic("no dtb found");
diff --git a/arch/mips/pic32/pic32mzda/init.c b/arch/mips/pic32/pic32mzda/init.c
index 50f376f058f4..f232c77ff526 100644
--- a/arch/mips/pic32/pic32mzda/init.c
+++ b/arch/mips/pic32/pic32mzda/init.c
@@ -28,7 +28,7 @@ static ulong get_fdtaddr(void)
 	if (fw_passed_dtb && !fw_arg2 && !fw_arg3)
 		return (ulong)fw_passed_dtb;
 
-	if (__dtb_start < __dtb_end)
+	if (&__dtb_start < &__dtb_end)
 		ftaddr = (ulong)__dtb_start;
 
 	return ftaddr;
diff --git a/arch/mips/ralink/of.c b/arch/mips/ralink/of.c
index cbae9d23ab7f..2c9af61efc20 100644
--- a/arch/mips/ralink/of.c
+++ b/arch/mips/ralink/of.c
@@ -75,7 +75,7 @@ void __init plat_mem_setup(void)
 	 */
 	if (fw_passed_dtb)
 		dtb = (void *)fw_passed_dtb;
-	else if (__dtb_start != __dtb_end)
+	else if (&__dtb_start != &__dtb_end)
 		dtb = (void *)__dtb_start;
 
 	__dt_setup_arch(dtb);

base-commit: 36bbbd0e234d817938bdc52121a0f5473b3e58f5
-- 
2.30.0


             reply	other threads:[~2021-01-05 20:19 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-05 20:18 Nathan Chancellor [this message]
2021-01-05 20:23 ` Florian Fainelli
2021-01-07 16:26 ` Thomas Bogendoerfer

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=20210105201827.51766-1-natechancellor@gmail.com \
    --to=natechancellor@gmail.com \
    --cc=bcm-kernel-feedback-list@broadcom.com \
    --cc=clang-built-linux@googlegroups.com \
    --cc=f.fainelli@gmail.com \
    --cc=john@phrozen.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mips@vger.kernel.org \
    --cc=ndesaulniers@google.com \
    --cc=tsbogend@alpha.franken.de \
    --subject='Re: [PATCH] MIPS: Use address-of operator on section symbols' \
    /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

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).