configs/qemu_mips64r6: fix Linux kernel build with gcc 10.x

From [1]

"GCC 10 (PR 91233) won't silently allow registers that are not architecturally
available to be present in the clobber list anymore, resulting in build failure
for mips*r6 targets in form of:
...
.../sysdep.h:146:2: error: the register ‘lo’ cannot be clobbered in ‘asm’ for the current target
  146 |  __asm__ volatile (	 \
      |  ^~~~~~~

This is because base R6 ISA doesn't define hi and lo registers w/o DSP extension.
This patch provides the alternative clobber list for r6 targets that won't include
those registers."

Since kernel 5.4 and mips support for generic vDSO [2], the kernel fails to build
for mips r6 cpus with gcc 10 for the same reason as glibc.

[1] https://sourceware.org/git/?p=glibc.git;a=commit;h=020b2a97bb15f807c0482f0faee2184ed05bcad8
[2] https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=24640f233b466051ad3a5d2786d2951e43026c9d

Fixes:
https://gitlab.com/kubu93/buildroot/-/jobs/655618363
https://gitlab.com/kubu93/buildroot/-/jobs/655618364

Signed-off-by: Romain Naour <romain.naour@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

diff --git a/board/qemu/mips64r6-malta/patches/linux/0001-mips-Do-not-include-hi-and-lo-in-clobber-list-for-R6.patch b/board/qemu/mips64r6-malta/patches/linux/0001-mips-Do-not-include-hi-and-lo-in-clobber-list-for-R6.patch
new file mode 100644 (file)
index 0000000..ad2647e
--- /dev/null
+++ b/board/qemu/mips64r6-malta/patches/linux/0001-mips-Do-not-include-hi-and-lo-in-clobber-list-for-R6.patch
@@ -0,0 +1,149 @@
+From cfb381d8f4b64f3752c95b4bdd787be63ef84fb2 Mon Sep 17 00:00:00 2001
+From: Romain Naour <romain.naour@gmail.com>
+Date: Sat, 25 Jul 2020 11:46:01 +0200
+Subject: [PATCH] mips: Do not include hi and lo in clobber list for R6
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+From [1]
+"GCC 10 (PR 91233) won't silently allow registers that are not architecturally
+available to be present in the clobber list anymore, resulting in build failure
+for mips*r6 targets in form of:
+...
+.../sysdep.h:146:2: error: the register ‘lo’ cannot be clobbered in ‘asm’ for the current target
+  146 |  __asm__ volatile (      \
+      |  ^~~~~~~
+
+This is because base R6 ISA doesn't define hi and lo registers w/o DSP extension.
+This patch provides the alternative clobber list for r6 targets that won't include
+those registers."
+
+Since kernel 5.4 and mips support for generic vDSO [2], the kernel fail to build
+for mips r6 cpus with gcc 10 for the same reason as glibc.
+
+[1] https://sourceware.org/git/?p=glibc.git;a=commit;h=020b2a97bb15f807c0482f0faee2184ed05bcad8
+[2] https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=24640f233b466051ad3a5d2786d2951e43026c9d
+
+Signed-off-by: Romain Naour <romain.naour@gmail.com>
+---
+ arch/mips/include/asm/vdso/gettimeofday.h | 45 +++++++++++++++++++++++
+ 1 file changed, 45 insertions(+)
+
+diff --git a/arch/mips/include/asm/vdso/gettimeofday.h b/arch/mips/include/asm/vdso/gettimeofday.h
+index 0ae9b4cbc153..ea600e0ebfe7 100644
+--- a/arch/mips/include/asm/vdso/gettimeofday.h
++++ b/arch/mips/include/asm/vdso/gettimeofday.h
+@@ -36,12 +36,21 @@ static __always_inline long gettimeofday_fallback(
+       register long nr asm("v0") = __NR_gettimeofday;
+       register long error asm("a3");
+ 
++#if MIPS_ISA_REV >= 6
++      asm volatile(
++      "       syscall\n"
++      : "=r" (ret), "=r" (error)
++      : "r" (tv), "r" (tz), "r" (nr)
++      : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
++        "$14", "$15", "$24", "$25", "memory");
++#else
+       asm volatile(
+       "       syscall\n"
+       : "=r" (ret), "=r" (error)
+       : "r" (tv), "r" (tz), "r" (nr)
+       : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
+         "$14", "$15", "$24", "$25", "hi", "lo", "memory");
++#endif
+ 
+       return error ? -ret : ret;
+ }
+@@ -60,12 +69,21 @@ static __always_inline long clock_gettime_fallback(
+ #endif
+       register long error asm("a3");
+ 
++#if MIPS_ISA_REV >= 6
++      asm volatile(
++      "       syscall\n"
++      : "=r" (ret), "=r" (error)
++      : "r" (clkid), "r" (ts), "r" (nr)
++      : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
++        "$14", "$15", "$24", "$25", "memory");
++#else
+       asm volatile(
+       "       syscall\n"
+       : "=r" (ret), "=r" (error)
+       : "r" (clkid), "r" (ts), "r" (nr)
+       : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
+         "$14", "$15", "$24", "$25", "hi", "lo", "memory");
++#endif
+ 
+       return error ? -ret : ret;
+ }
+@@ -84,12 +102,21 @@ static __always_inline int clock_getres_fallback(
+ #endif
+       register long error asm("a3");
+ 
++#if MIPS_ISA_REV >= 6
++      asm volatile(
++      "       syscall\n"
++      : "=r" (ret), "=r" (error)
++      : "r" (clkid), "r" (ts), "r" (nr)
++      : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
++        "$14", "$15", "$24", "$25", "memory");
++#else
+       asm volatile(
+       "       syscall\n"
+       : "=r" (ret), "=r" (error)
+       : "r" (clkid), "r" (ts), "r" (nr)
+       : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
+         "$14", "$15", "$24", "$25", "hi", "lo", "memory");
++#endif
+ 
+       return error ? -ret : ret;
+ }
+@@ -108,12 +135,21 @@ static __always_inline long clock_gettime32_fallback(
+       register long nr asm("v0") = __NR_clock_gettime;
+       register long error asm("a3");
+ 
++#if MIPS_ISA_REV >= 6
++      asm volatile(
++      "       syscall\n"
++      : "=r" (ret), "=r" (error)
++      : "r" (clkid), "r" (ts), "r" (nr)
++      : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
++        "$14", "$15", "$24", "$25", "memory");
++#else
+       asm volatile(
+       "       syscall\n"
+       : "=r" (ret), "=r" (error)
+       : "r" (clkid), "r" (ts), "r" (nr)
+       : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
+         "$14", "$15", "$24", "$25", "hi", "lo", "memory");
++#endif
+ 
+       return error ? -ret : ret;
+ }
+@@ -128,12 +164,21 @@ static __always_inline int clock_getres32_fallback(
+       register long nr asm("v0") = __NR_clock_getres;
+       register long error asm("a3");
+ 
++#if MIPS_ISA_REV >= 6
++      asm volatile(
++      "       syscall\n"
++      : "=r" (ret), "=r" (error)
++      : "r" (clkid), "r" (ts), "r" (nr)
++      : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
++        "$14", "$15", "$24", "$25", "memory");
++#else
+       asm volatile(
+       "       syscall\n"
+       : "=r" (ret), "=r" (error)
+       : "r" (clkid), "r" (ts), "r" (nr)
+       : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
+         "$14", "$15", "$24", "$25", "hi", "lo", "memory");
++#endif
+ 
+       return error ? -ret : ret;
+ }
+-- 
+2.25.4
+

diff --git a/board/qemu/mips64r6el-malta/patches/linux/0001-mips-Do-not-include-hi-and-lo-in-clobber-list-for-R6.patch b/board/qemu/mips64r6el-malta/patches/linux/0001-mips-Do-not-include-hi-and-lo-in-clobber-list-for-R6.patch
new file mode 100644 (file)
index 0000000..ad2647e
--- /dev/null
+++ b/board/qemu/mips64r6el-malta/patches/linux/0001-mips-Do-not-include-hi-and-lo-in-clobber-list-for-R6.patch
@@ -0,0 +1,149 @@
+From cfb381d8f4b64f3752c95b4bdd787be63ef84fb2 Mon Sep 17 00:00:00 2001
+From: Romain Naour <romain.naour@gmail.com>
+Date: Sat, 25 Jul 2020 11:46:01 +0200
+Subject: [PATCH] mips: Do not include hi and lo in clobber list for R6
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+From [1]
+"GCC 10 (PR 91233) won't silently allow registers that are not architecturally
+available to be present in the clobber list anymore, resulting in build failure
+for mips*r6 targets in form of:
+...
+.../sysdep.h:146:2: error: the register ‘lo’ cannot be clobbered in ‘asm’ for the current target
+  146 |  __asm__ volatile (      \
+      |  ^~~~~~~
+
+This is because base R6 ISA doesn't define hi and lo registers w/o DSP extension.
+This patch provides the alternative clobber list for r6 targets that won't include
+those registers."
+
+Since kernel 5.4 and mips support for generic vDSO [2], the kernel fail to build
+for mips r6 cpus with gcc 10 for the same reason as glibc.
+
+[1] https://sourceware.org/git/?p=glibc.git;a=commit;h=020b2a97bb15f807c0482f0faee2184ed05bcad8
+[2] https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=24640f233b466051ad3a5d2786d2951e43026c9d
+
+Signed-off-by: Romain Naour <romain.naour@gmail.com>
+---
+ arch/mips/include/asm/vdso/gettimeofday.h | 45 +++++++++++++++++++++++
+ 1 file changed, 45 insertions(+)
+
+diff --git a/arch/mips/include/asm/vdso/gettimeofday.h b/arch/mips/include/asm/vdso/gettimeofday.h
+index 0ae9b4cbc153..ea600e0ebfe7 100644
+--- a/arch/mips/include/asm/vdso/gettimeofday.h
++++ b/arch/mips/include/asm/vdso/gettimeofday.h
+@@ -36,12 +36,21 @@ static __always_inline long gettimeofday_fallback(
+       register long nr asm("v0") = __NR_gettimeofday;
+       register long error asm("a3");
+ 
++#if MIPS_ISA_REV >= 6
++      asm volatile(
++      "       syscall\n"
++      : "=r" (ret), "=r" (error)
++      : "r" (tv), "r" (tz), "r" (nr)
++      : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
++        "$14", "$15", "$24", "$25", "memory");
++#else
+       asm volatile(
+       "       syscall\n"
+       : "=r" (ret), "=r" (error)
+       : "r" (tv), "r" (tz), "r" (nr)
+       : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
+         "$14", "$15", "$24", "$25", "hi", "lo", "memory");
++#endif
+ 
+       return error ? -ret : ret;
+ }
+@@ -60,12 +69,21 @@ static __always_inline long clock_gettime_fallback(
+ #endif
+       register long error asm("a3");
+ 
++#if MIPS_ISA_REV >= 6
++      asm volatile(
++      "       syscall\n"
++      : "=r" (ret), "=r" (error)
++      : "r" (clkid), "r" (ts), "r" (nr)
++      : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
++        "$14", "$15", "$24", "$25", "memory");
++#else
+       asm volatile(
+       "       syscall\n"
+       : "=r" (ret), "=r" (error)
+       : "r" (clkid), "r" (ts), "r" (nr)
+       : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
+         "$14", "$15", "$24", "$25", "hi", "lo", "memory");
++#endif
+ 
+       return error ? -ret : ret;
+ }
+@@ -84,12 +102,21 @@ static __always_inline int clock_getres_fallback(
+ #endif
+       register long error asm("a3");
+ 
++#if MIPS_ISA_REV >= 6
++      asm volatile(
++      "       syscall\n"
++      : "=r" (ret), "=r" (error)
++      : "r" (clkid), "r" (ts), "r" (nr)
++      : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
++        "$14", "$15", "$24", "$25", "memory");
++#else
+       asm volatile(
+       "       syscall\n"
+       : "=r" (ret), "=r" (error)
+       : "r" (clkid), "r" (ts), "r" (nr)
+       : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
+         "$14", "$15", "$24", "$25", "hi", "lo", "memory");
++#endif
+ 
+       return error ? -ret : ret;
+ }
+@@ -108,12 +135,21 @@ static __always_inline long clock_gettime32_fallback(
+       register long nr asm("v0") = __NR_clock_gettime;
+       register long error asm("a3");
+ 
++#if MIPS_ISA_REV >= 6
++      asm volatile(
++      "       syscall\n"
++      : "=r" (ret), "=r" (error)
++      : "r" (clkid), "r" (ts), "r" (nr)
++      : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
++        "$14", "$15", "$24", "$25", "memory");
++#else
+       asm volatile(
+       "       syscall\n"
+       : "=r" (ret), "=r" (error)
+       : "r" (clkid), "r" (ts), "r" (nr)
+       : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
+         "$14", "$15", "$24", "$25", "hi", "lo", "memory");
++#endif
+ 
+       return error ? -ret : ret;
+ }
+@@ -128,12 +164,21 @@ static __always_inline int clock_getres32_fallback(
+       register long nr asm("v0") = __NR_clock_getres;
+       register long error asm("a3");
+ 
++#if MIPS_ISA_REV >= 6
++      asm volatile(
++      "       syscall\n"
++      : "=r" (ret), "=r" (error)
++      : "r" (clkid), "r" (ts), "r" (nr)
++      : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
++        "$14", "$15", "$24", "$25", "memory");
++#else
+       asm volatile(
+       "       syscall\n"
+       : "=r" (ret), "=r" (error)
+       : "r" (clkid), "r" (ts), "r" (nr)
+       : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
+         "$14", "$15", "$24", "$25", "hi", "lo", "memory");
++#endif
+ 
+       return error ? -ret : ret;
+ }
+-- 
+2.25.4
+

diff --git a/configs/qemu_mips64r6_malta_defconfig b/configs/qemu_mips64r6_malta_defconfig
index 16bc69299607a33dc98db18bf00aca8a2d241f2c..d53e8e114d4b057dadea137add3df18ebb5616aa 100644 (file)
--- a/configs/qemu_mips64r6_malta_defconfig
+++ b/configs/qemu_mips64r6_malta_defconfig
@@ -24,6 +24,7 @@ BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="5.4.42"
 BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
 BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="board/qemu/mips64r6-malta/linux.config"
 BR2_LINUX_KERNEL_VMLINUX=y
+BR2_GLOBAL_PATCH_DIR="board/qemu/mips64r6-malta/patches"
 
 # Serial port config
 BR2_TARGET_GENERIC_GETTY=y

diff --git a/configs/qemu_mips64r6el_malta_defconfig b/configs/qemu_mips64r6el_malta_defconfig
index 33b91f3ac1ef52ddc22654853364dafc3b2725ce..9f4573a4a91fca3e9131a019cb8b81dcb58a62df 100644 (file)
--- a/configs/qemu_mips64r6el_malta_defconfig
+++ b/configs/qemu_mips64r6el_malta_defconfig
@@ -24,6 +24,7 @@ BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="5.4.42"
 BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
 BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="board/qemu/mips64r6el-malta/linux.config"
 BR2_LINUX_KERNEL_VMLINUX=y
+BR2_GLOBAL_PATCH_DIR="board/qemu/mips64r6el-malta/patches"
 
 # Serial port config
 BR2_TARGET_GENERIC_GETTY=y