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authorLinus Torvalds <torvalds@linux-foundation.org>2017-12-13 20:13:05 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-12-13 20:13:05 -0800
commit4e746cf4f721d6397bace501f5feadb46eec1314 (patch)
treecdae0fd17a74cae07c5fb55c7112d8aa038b7837 /arch
parentd39a01eff9af1045f6e30ff9db40310517c4b45f (diff)
parent27b0174525325bf18919597016483a709f3372f8 (diff)
Merge tag 'riscv-for-linus-4.15-rc4-riscv_fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/palmer/linux
Pull RISC-V fixes from Palmer Dabbelt: "This contains three small fixes: - A fix to a typo in sys_riscv_flush_icache. This only effects error handling, but I think it's a small and obvious enough change that it's sane outside the merge window. - The addition of smp_mb__after_spinlock(), which was recently removed due to an incorrect comment. This is largly a comment change (as there's a big one now), and while it's necessary for complience with the RISC-V memory model the lack of this fence shouldn't manifest as a bug on current implementations. Nonetheless, it still seems saner to have the fence in 4.15. - The removal of some of the HVC_RISCV_SBI driver that snuck into the arch port. This is compile-time dead code in 4.15 (as the driver isn't in yet), and during the review process we found a better way to implement early printk on RISC-V. While this change doesn't do anything, it will make staging our HVC driver easier: without this change the HVC driver we hope to upstream won't build on 4.15 (because the 4.15 arch code would reference a function that no longer exists). I don't think this is the last patch set we'll want for 4.15: I think I'll want to remove some of the first-level irqchip driver that snuck in as well, which will look a lot like the HVC patch here. This is pending some asm-generic cleanup I'm doing that I haven't quite gotten clean enough to send out yet, though, but hopefully it'll be ready by next week (and still OK for that late)" * tag 'riscv-for-linus-4.15-rc4-riscv_fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/palmer/linux: RISC-V: Remove unused CONFIG_HVC_RISCV_SBI code RISC-V: Resurrect smp_mb__after_spinlock() RISC-V: Logical vs Bitwise typo
Diffstat (limited to 'arch')
-rw-r--r--arch/riscv/include/asm/barrier.h19
-rw-r--r--arch/riscv/kernel/setup.c11
-rw-r--r--arch/riscv/kernel/sys_riscv.c2
3 files changed, 20 insertions, 12 deletions
diff --git a/arch/riscv/include/asm/barrier.h b/arch/riscv/include/asm/barrier.h
index 773c4e039cd7..c0319cbf1eec 100644
--- a/arch/riscv/include/asm/barrier.h
+++ b/arch/riscv/include/asm/barrier.h
@@ -38,6 +38,25 @@
#define smp_rmb() RISCV_FENCE(r,r)
#define smp_wmb() RISCV_FENCE(w,w)
+/*
+ * This is a very specific barrier: it's currently only used in two places in
+ * the kernel, both in the scheduler. See include/linux/spinlock.h for the two
+ * orderings it guarantees, but the "critical section is RCsc" guarantee
+ * mandates a barrier on RISC-V. The sequence looks like:
+ *
+ * lr.aq lock
+ * sc lock <= LOCKED
+ * smp_mb__after_spinlock()
+ * // critical section
+ * lr lock
+ * sc.rl lock <= UNLOCKED
+ *
+ * The AQ/RL pair provides a RCpc critical section, but there's not really any
+ * way we can take advantage of that here because the ordering is only enforced
+ * on that one lock. Thus, we're just doing a full fence.
+ */
+#define smp_mb__after_spinlock() RISCV_FENCE(rw,rw)
+
#include <asm-generic/barrier.h>
#endif /* __ASSEMBLY__ */
diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index 8fbb6749910d..cb7b0c63014e 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -38,10 +38,6 @@
#include <asm/tlbflush.h>
#include <asm/thread_info.h>
-#ifdef CONFIG_HVC_RISCV_SBI
-#include <asm/hvc_riscv_sbi.h>
-#endif
-
#ifdef CONFIG_DUMMY_CONSOLE
struct screen_info screen_info = {
.orig_video_lines = 30,
@@ -212,13 +208,6 @@ static void __init setup_bootmem(void)
void __init setup_arch(char **cmdline_p)
{
-#if defined(CONFIG_HVC_RISCV_SBI)
- if (likely(early_console == NULL)) {
- early_console = &riscv_sbi_early_console_dev;
- register_console(early_console);
- }
-#endif
-
#ifdef CONFIG_CMDLINE_BOOL
#ifdef CONFIG_CMDLINE_OVERRIDE
strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
diff --git a/arch/riscv/kernel/sys_riscv.c b/arch/riscv/kernel/sys_riscv.c
index a2ae936a093e..79c78668258e 100644
--- a/arch/riscv/kernel/sys_riscv.c
+++ b/arch/riscv/kernel/sys_riscv.c
@@ -70,7 +70,7 @@ SYSCALL_DEFINE3(riscv_flush_icache, uintptr_t, start, uintptr_t, end,
bool local = (flags & SYS_RISCV_FLUSH_ICACHE_LOCAL) != 0;
/* Check the reserved flags. */
- if (unlikely(flags & !SYS_RISCV_FLUSH_ICACHE_ALL))
+ if (unlikely(flags & ~SYS_RISCV_FLUSH_ICACHE_ALL))
return -EINVAL;
flush_icache_mm(mm, local);