[tip: timers/core] ARM: vdso: Set BUILD_VDSO32 and provide 32bit fallbacks

[tip-bot2 for Thomas Gleixner]

The following commit has been merged into the timers/core branch of tip:

Commit-ID:     715f23b6104aa297feea20d4f200ca81941e23de
Gitweb:        https://git.kernel.org/tip/715f23b6104aa297feea20d4f200ca81941e23de
Author:        Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate:    Tue, 14 Jan 2020 09:41:09 +01:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Tue, 14 Jan 2020 12:20:43 +01:00

ARM: vdso: Set BUILD_VDSO32 and provide 32bit fallbacks

Setting BUILD_VDSO32 is required to expose the legacy 32bit interfaces in
the generic VDSO code which are going to be hidden behind an #ifdef
BUILD_VDSO32.

The 32bit fallbacks are necessary to remove the existing
VDSO_HAS_32BIT_FALLBACK hackery.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Tested-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/87tv4zq9dc.fsf@xxxxxxxxxxxxxxxxxxxxxxx
---
 arch/arm/include/asm/vdso/gettimeofday.h | 36 +++++++++++++++++++++++-
 arch/arm/vdso/Makefile                   |  2 +-
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/vdso/gettimeofday.h b/arch/arm/include/asm/vdso/gettimeofday.h
index 0ad2429..fe6e1f6 100644
--- a/arch/arm/include/asm/vdso/gettimeofday.h
+++ b/arch/arm/include/asm/vdso/gettimeofday.h
@@ -52,6 +52,24 @@ static __always_inline long clock_gettime_fallback(
 	return ret;
 }
 
+static __always_inline long clock_gettime32_fallback(
+					clockid_t _clkid,
+					struct old_timespec32 *_ts)
+{
+	register struct old_timespec32 *ts asm("r1") = _ts;
+	register clockid_t clkid asm("r0") = _clkid;
+	register long ret asm ("r0");
+	register long nr asm("r7") = __NR_clock_gettime;
+
+	asm volatile(
+	"	swi #0\n"
+	: "=r" (ret)
+	: "r" (clkid), "r" (ts), "r" (nr)
+	: "memory");
+
+	return ret;
+}
+
 static __always_inline int clock_getres_fallback(
 					clockid_t _clkid,
 					struct __kernel_timespec *_ts)
@@ -70,6 +88,24 @@ static __always_inline int clock_getres_fallback(
 	return ret;
 }
 
+static __always_inline int clock_getres32_fallback(
+					clockid_t _clkid,
+					struct old_timespec32 *_ts)
+{
+	register struct old_timespec32 *ts asm("r1") = _ts;
+	register clockid_t clkid asm("r0") = _clkid;
+	register long ret asm ("r0");
+	register long nr asm("r7") = __NR_clock_getres;
+
+	asm volatile(
+	"       swi #0\n"
+	: "=r" (ret)
+	: "r" (clkid), "r" (ts), "r" (nr)
+	: "memory");
+
+	return ret;
+}
+
 static __always_inline u64 __arch_get_hw_counter(int clock_mode)
 {
 #ifdef CONFIG_ARM_ARCH_TIMER
diff --git a/arch/arm/vdso/Makefile b/arch/arm/vdso/Makefile
index 0fda344..1babb39 100644
--- a/arch/arm/vdso/Makefile
+++ b/arch/arm/vdso/Makefile
@@ -14,7 +14,7 @@ targets := $(obj-vdso) vdso.so vdso.so.dbg vdso.so.raw vdso.lds
 obj-vdso := $(addprefix $(obj)/, $(obj-vdso))
 
 ccflags-y := -fPIC -fno-common -fno-builtin -fno-stack-protector
-ccflags-y += -DDISABLE_BRANCH_PROFILING
+ccflags-y += -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO32
 
 ldflags-$(CONFIG_CPU_ENDIAN_BE8) := --be8
 ldflags-y := -Bsymbolic --no-undefined -soname=linux-vdso.so.1 \