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authorEugeniy Paltsev <eugeniy.paltsev@synopsys.com>2019-01-30 19:32:41 +0300
committerVineet Gupta <vgupta@synopsys.com>2019-02-25 23:10:58 +0300
commit76551468833cd5c356b1d9ff4bc9393fcf768a59 (patch)
tree8e2552cc13389bc3c90c916b0342bfac7f3a90b1
parent4d1e7918aae59ef504f5170a4f0c7ae82339fcb2 (diff)
downloadlinux-76551468833cd5c356b1d9ff4bc9393fcf768a59.tar.xz
ARCv2: Add explcit unaligned access support (and ability to disable too)
As of today we enable unaligned access unconditionally on ARCv2. Do this under a Kconfig option to allow disable it for test, benchmarking etc. Also while at it - Select HAVE_EFFICIENT_UNALIGNED_ACCESS - Although gcc defaults to unaligned access (since GNU 2018.03), add the right toggles for enabling or disabling as appropriate - update bootlog to prints both HW feature status (exists, enabled/disabled) and SW status (used / not used). - wire up the relaxed memcpy for unaligned access Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com> [vgupta: squashed patches, handle gcc -mno-unaligned-access quick]
-rw-r--r--arch/arc/Kconfig9
-rw-r--r--arch/arc/Makefile6
-rw-r--r--arch/arc/include/asm/arcregs.h1
-rw-r--r--arch/arc/include/asm/irqflags-arcv2.h8
-rw-r--r--arch/arc/kernel/head.S5
-rw-r--r--arch/arc/kernel/intc-arcv2.c2
-rw-r--r--arch/arc/kernel/setup.c25
-rw-r--r--arch/arc/kernel/troubleshoot.c5
-rw-r--r--arch/arc/lib/Makefile8
9 files changed, 56 insertions, 13 deletions
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index d750b302d5ab..95fb11a85566 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -386,6 +386,15 @@ config ARC_HAS_SWAPE
if ISA_ARCV2
+config ARC_USE_UNALIGNED_MEM_ACCESS
+ bool "Enable unaligned access in HW"
+ default y
+ select HAVE_EFFICIENT_UNALIGNED_ACCESS
+ help
+ The ARC HS architecture supports unaligned memory access
+ which is disabled by default. Enable unaligned access in
+ hardware and use software to use it
+
config ARC_HAS_LL64
bool "Insn: 64bit LDD/STD"
help
diff --git a/arch/arc/Makefile b/arch/arc/Makefile
index df00578c279d..e2b991f75bc5 100644
--- a/arch/arc/Makefile
+++ b/arch/arc/Makefile
@@ -28,6 +28,12 @@ cflags-$(CONFIG_ARC_HAS_SWAPE) += -mswape
ifdef CONFIG_ISA_ARCV2
+ifdef CONFIG_ARC_USE_UNALIGNED_MEM_ACCESS
+cflags-y += -munaligned-access
+else
+cflags-y += -mno-unaligned-access
+endif
+
ifndef CONFIG_ARC_HAS_LL64
cflags-y += -mno-ll64
endif
diff --git a/arch/arc/include/asm/arcregs.h b/arch/arc/include/asm/arcregs.h
index a27eafdc8260..0c13317af1d6 100644
--- a/arch/arc/include/asm/arcregs.h
+++ b/arch/arc/include/asm/arcregs.h
@@ -82,6 +82,7 @@
#define ECR_V_DTLB_MISS 0x05
#define ECR_V_PROTV 0x06
#define ECR_V_TRAP 0x09
+#define ECR_V_MISALIGN 0x0d
#endif
/* DTLB Miss and Protection Violation Cause Codes */
diff --git a/arch/arc/include/asm/irqflags-arcv2.h b/arch/arc/include/asm/irqflags-arcv2.h
index 8a4f77ea3238..e66d0339e1d8 100644
--- a/arch/arc/include/asm/irqflags-arcv2.h
+++ b/arch/arc/include/asm/irqflags-arcv2.h
@@ -44,7 +44,13 @@
#define ARCV2_IRQ_DEF_PRIO 1
/* seed value for status register */
-#define ISA_INIT_STATUS_BITS (STATUS_IE_MASK | STATUS_AD_MASK | \
+#ifdef CONFIG_ARC_USE_UNALIGNED_MEM_ACCESS
+#define __AD_ENB STATUS_AD_MASK
+#else
+#define __AD_ENB 0
+#endif
+
+#define ISA_INIT_STATUS_BITS (STATUS_IE_MASK | __AD_ENB | \
(ARCV2_IRQ_DEF_PRIO << 1))
#ifndef __ASSEMBLY__
diff --git a/arch/arc/kernel/head.S b/arch/arc/kernel/head.S
index 30e090625916..36774348d23b 100644
--- a/arch/arc/kernel/head.S
+++ b/arch/arc/kernel/head.S
@@ -54,7 +54,12 @@
; gcc 7.3.1 (ARC GNU 2018.03) onwards generates unaligned access
; by default
lr r5, [status32]
+#ifdef CONFIG_ARC_USE_UNALIGNED_MEM_ACCESS
bset r5, r5, STATUS_AD_BIT
+#else
+ ; Although disabled at reset, bootloader might have enabled it
+ bclr r5, r5, STATUS_AD_BIT
+#endif
kflag r5
#endif
.endm
diff --git a/arch/arc/kernel/intc-arcv2.c b/arch/arc/kernel/intc-arcv2.c
index cf18b3e5a934..c0d0124de089 100644
--- a/arch/arc/kernel/intc-arcv2.c
+++ b/arch/arc/kernel/intc-arcv2.c
@@ -95,7 +95,7 @@ void arc_init_IRQ(void)
/* setup status32, don't enable intr yet as kernel doesn't want */
tmp = read_aux_reg(ARC_REG_STATUS32);
- tmp |= STATUS_AD_MASK | (ARCV2_IRQ_DEF_PRIO << 1);
+ tmp |= ARCV2_IRQ_DEF_PRIO << 1;
tmp &= ~STATUS_IE_MASK;
asm volatile("kflag %0 \n"::"r"(tmp));
}
diff --git a/arch/arc/kernel/setup.c b/arch/arc/kernel/setup.c
index 7b2340996cf8..2266e4ee4142 100644
--- a/arch/arc/kernel/setup.c
+++ b/arch/arc/kernel/setup.c
@@ -263,7 +263,7 @@ static char *arc_cpu_mumbojumbo(int cpu_id, char *buf, int len)
{
struct cpuinfo_arc *cpu = &cpuinfo_arc700[cpu_id];
struct bcr_identity *core = &cpu->core;
- int i, n = 0, ua = 0;
+ int n = 0;
FIX_PTR(cpu);
@@ -283,16 +283,23 @@ static char *arc_cpu_mumbojumbo(int cpu_id, char *buf, int len)
IS_AVAIL2(cpu->extn.rtc, "RTC [UP 64-bit] ", CONFIG_ARC_TIMERS_64BIT),
IS_AVAIL2(cpu->extn.gfrc, "GFRC [SMP 64-bit] ", CONFIG_ARC_TIMERS_64BIT));
-#ifdef __ARC_UNALIGNED__
- ua = 1;
+ n += scnprintf(buf + n, len - n, "%s%s%s%s%s%s",
+ IS_AVAIL2(cpu->isa.atomic, "atomic ", CONFIG_ARC_HAS_LLSC),
+ IS_AVAIL2(cpu->isa.ldd, "ll64 ", CONFIG_ARC_HAS_LL64),
+ IS_AVAIL2(cpu->isa.unalign, "unalign ", CONFIG_ARC_USE_UNALIGNED_MEM_ACCESS));
+
+#if defined(__ARC_UNALIGNED__) && !defined(CONFIG_ARC_USE_UNALIGNED_MEM_ACCESS)
+ /*
+ * gcc 7.3.1 (GNU 2018.03) onwards generate unaligned access by default
+ * but -mno-unaligned-access to disable that didn't work until gcc 8.2.1
+ * (GNU 2019.03). So landing here implies the interim period, when
+ * despite Kconfig being off, gcc is generating unaligned accesses which
+ * could bomb later on. So better to disallow such broken builds
+ */
+ BUILD_BUG_ON_MSG(1, "gcc doesn't support -mno-unaligned-access");
#endif
- n += i = scnprintf(buf + n, len - n, "%s%s%s%s%s%s",
- IS_AVAIL2(cpu->isa.atomic, "atomic ", CONFIG_ARC_HAS_LLSC),
- IS_AVAIL2(cpu->isa.ldd, "ll64 ", CONFIG_ARC_HAS_LL64),
- IS_AVAIL1(cpu->isa.unalign, "unalign "), IS_USED_RUN(ua));
- if (i)
- n += scnprintf(buf + n, len - n, "\n\t\t: ");
+ n += scnprintf(buf + n, len - n, "\n\t\t: ");
if (cpu->extn_mpy.ver) {
if (cpu->extn_mpy.ver <= 0x2) { /* ARCompact */
diff --git a/arch/arc/kernel/troubleshoot.c b/arch/arc/kernel/troubleshoot.c
index 215f515442e0..b0aa8c028331 100644
--- a/arch/arc/kernel/troubleshoot.c
+++ b/arch/arc/kernel/troubleshoot.c
@@ -145,7 +145,8 @@ static void show_ecr_verbose(struct pt_regs *regs)
} else if (vec == ECR_V_PROTV) {
if (cause_code == ECR_C_PROTV_INST_FETCH)
pr_cont("Execute from Non-exec Page\n");
- else if (cause_code == ECR_C_PROTV_MISALIG_DATA)
+ else if (cause_code == ECR_C_PROTV_MISALIG_DATA &&
+ IS_ENABLED(CONFIG_ISA_ARCOMPACT))
pr_cont("Misaligned r/w from 0x%08lx\n", address);
else
pr_cont("%s access not allowed on page\n",
@@ -161,6 +162,8 @@ static void show_ecr_verbose(struct pt_regs *regs)
pr_cont("Bus Error from Data Mem\n");
else
pr_cont("Bus Error, check PRM\n");
+ } else if (vec == ECR_V_MISALIGN) {
+ pr_cont("Misaligned r/w from 0x%08lx\n", address);
#endif
} else if (vec == ECR_V_TRAP) {
if (regs->ecr_param == 5)
diff --git a/arch/arc/lib/Makefile b/arch/arc/lib/Makefile
index b1656d156097..f7537b466b23 100644
--- a/arch/arc/lib/Makefile
+++ b/arch/arc/lib/Makefile
@@ -8,4 +8,10 @@
lib-y := strchr-700.o strcpy-700.o strlen.o memcmp.o
lib-$(CONFIG_ISA_ARCOMPACT) += memcpy-700.o memset.o strcmp.o
-lib-$(CONFIG_ISA_ARCV2) += memcpy-archs.o memset-archs.o strcmp-archs.o
+lib-$(CONFIG_ISA_ARCV2) += memset-archs.o strcmp-archs.o
+
+ifdef CONFIG_ARC_USE_UNALIGNED_MEM_ACCESS
+lib-$(CONFIG_ISA_ARCV2) +=memcpy-archs-unaligned.o
+else
+lib-$(CONFIG_ISA_ARCV2) +=memcpy-archs.o
+endif