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RISC-V Fixes for 6.10-rc6

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* A fix for vector load/store instruction decoding, which could result
   in reserved vector element length encodings decoding as valid vector
   instructions.
 * Instruction patching now aggressively flushes the local instruction
   cache, to avoid situations where patching functions on the flush path
   results in torn instructions being fetched.
 * A fix to prevent the stack walker from showing up as part of traces.
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Merge tag 'riscv-for-linus-6.10-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V fixes from Palmer Dabbelt:

 - A fix for vector load/store instruction decoding, which could result
   in reserved vector element length encodings decoding as valid vector
   instructions.

 - Instruction patching now aggressively flushes the local instruction
   cache, to avoid situations where patching functions on the flush path
   results in torn instructions being fetched.

 - A fix to prevent the stack walker from showing up as part of traces.

* tag 'riscv-for-linus-6.10-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  riscv: stacktrace: convert arch_stack_walk() to noinstr
  riscv: patch: Flush the icache right after patching to avoid illegal insns
  RISC-V: fix vector insn load/store width mask
This commit is contained in:
Linus Torvalds 2024-06-28 16:14:59 -07:00
commit de0a9f4486
4 changed files with 22 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/riscv/include/asm/insn.h
View File

@ -145,7 +145,7 @@
/* parts of opcode for RVF, RVD and RVQ */
#define RVFDQ_FL_FS_WIDTH_OFF 12
#define RVFDQ_FL_FS_WIDTH_MASK GENMASK(3, 0)
#define RVFDQ_FL_FS_WIDTH_MASK GENMASK(2, 0)
#define RVFDQ_FL_FS_WIDTH_W 2
#define RVFDQ_FL_FS_WIDTH_D 3
#define RVFDQ_LS_FS_WIDTH_Q 4

7
arch/riscv/kernel/ftrace.c
View File

@ -120,9 +120,6 @@ int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec)
out = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
mutex_unlock(&text_mutex);
if (!mod)
local_flush_icache_range(rec->ip, rec->ip + MCOUNT_INSN_SIZE);
return out;
}
@ -156,9 +153,9 @@ static int __ftrace_modify_code(void *data)
} else {
while (atomic_read(&param->cpu_count) <= num_online_cpus())
cpu_relax();
}
local_flush_icache_all();
local_flush_icache_all();
}
return 0;
}

26
arch/riscv/kernel/patch.c
View File

@ -89,6 +89,14 @@ static int __patch_insn_set(void *addr, u8 c, size_t len)
memset(waddr, c, len);
/*
* We could have just patched a function that is about to be
* called so make sure we don't execute partially patched
* instructions by flushing the icache as soon as possible.
*/
local_flush_icache_range((unsigned long)waddr,
(unsigned long)waddr + len);
patch_unmap(FIX_TEXT_POKE0);
if (across_pages)
@ -135,6 +143,14 @@ static int __patch_insn_write(void *addr, const void *insn, size_t len)
ret = copy_to_kernel_nofault(waddr, insn, len);
/*
* We could have just patched a function that is about to be
* called so make sure we don't execute partially patched
* instructions by flushing the icache as soon as possible.
*/
local_flush_icache_range((unsigned long)waddr,
(unsigned long)waddr + len);
patch_unmap(FIX_TEXT_POKE0);
if (across_pages)
@ -189,9 +205,6 @@ int patch_text_set_nosync(void *addr, u8 c, size_t len)
ret = patch_insn_set(tp, c, len);
if (!ret)
flush_icache_range((uintptr_t)tp, (uintptr_t)tp + len);
return ret;
}
NOKPROBE_SYMBOL(patch_text_set_nosync);
@ -224,9 +237,6 @@ int patch_text_nosync(void *addr, const void *insns, size_t len)
ret = patch_insn_write(tp, insns, len);
if (!ret)
flush_icache_range((uintptr_t) tp, (uintptr_t) tp + len);
return ret;
}
NOKPROBE_SYMBOL(patch_text_nosync);
@ -253,9 +263,9 @@ static int patch_text_cb(void *data)
} else {
while (atomic_read(&patch->cpu_count) <= num_online_cpus())
cpu_relax();
}
local_flush_icache_all();
local_flush_icache_all();
}
return ret;
}

2
arch/riscv/kernel/stacktrace.c
View File

@ -156,7 +156,7 @@ unsigned long __get_wchan(struct task_struct *task)
return pc;
}
noinline void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
noinline noinstr void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
struct task_struct *task, struct pt_regs *regs)
{
walk_stackframe(task, regs, consume_entry, cookie);