From 86ad5c97ce5ccdda1459d35370fd5e105721bb8d Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Sat, 9 Dec 2017 14:49:14 +0300 Subject: [PATCH 1/3] RISC-V: Logical vs Bitwise typo In the current code, there is a ! logical NOT where a bitwise ~ NOT was intended. It means that we never return -EINVAL. Signed-off-by: Dan Carpenter Signed-off-by: Palmer Dabbelt --- arch/riscv/kernel/sys_riscv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) 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); From 3cfa5008081db845c6c53d531ec34e9c84a9fd99 Mon Sep 17 00:00:00 2001 From: Palmer Dabbelt Date: Tue, 5 Dec 2017 17:48:11 -0800 Subject: [PATCH 2/3] RISC-V: Resurrect smp_mb__after_spinlock() I removed this last week because of an incorrect comment: smp_mb__after_spinlock() is actually still used, and is necessary on RISC-V. It's been resurrected, with a comment that describes what it actually does this time. Thanks to Andrea for finding the bug! Fixes: 3343eb6806f3 ("RISC-V: Remove smb_mb__{before,after}_spinlock()") CC: Andrea Parri Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/barrier.h | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) 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 #endif /* __ASSEMBLY__ */ From 27b0174525325bf18919597016483a709f3372f8 Mon Sep 17 00:00:00 2001 From: Palmer Dabbelt Date: Fri, 8 Dec 2017 11:23:23 -0800 Subject: [PATCH 3/3] RISC-V: Remove unused CONFIG_HVC_RISCV_SBI code This is code that probably should never have made it into the kernel in the first place: it depends on a driver that hadn't been reviewed yet. During the HVC_SBI_RISCV review process a better way of doing this was suggested, but that means this code is defunct. It's compile-time disabled in 4.15 because the driver isn't in, so I think it's safe to just remove this for now. CC: Greg KH Signed-off-by: Palmer Dabbelt --- arch/riscv/kernel/setup.c | 11 ----------- 1 file changed, 11 deletions(-) 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 #include -#ifdef CONFIG_HVC_RISCV_SBI -#include -#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);