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

Author: torvalds

arch/riscv/include/asm/insn.h

@@ -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

arch/riscv/kernel/ftrace.c

@@ -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;
 }

arch/riscv/kernel/patch.c

@@ -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;
 }

arch/riscv/kernel/stacktrace.c

@@ -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);