[PATCH AUTOSEL 6.14 2/9] riscv: tracing: Fix __write_overflow_field in ftrace_partial_regs()

[PATCH AUTOSEL 6.14 2/9] riscv: tracing: Fix __write_overflow_field in ftrace_partial_regs()

[Sasha Levin]

From: Charlie Jenkins <charlie@rivosinc.com>

[ Upstream commit bba547810c66434475d8800b3411c59ef71eafe9 ]

The size of &regs->a0 is unknown, causing the error:

../include/linux/fortify-string.h:571:25: warning: call to
'__write_overflow_field' declared with attribute warning: detected write
beyond size of field (1st parameter); maybe use struct_group()?
[-Wattribute-warning]

Fix this by wrapping the required registers in pt_regs with
struct_group() and reference the group when doing the offending
memcpy().

Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Tested-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20250224-fix_ftrace_partial_regs-v1-1-54b906417e86@rivosinc.com
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/riscv/include/asm/ftrace.h |  2 +-
 arch/riscv/include/asm/ptrace.h | 18 ++++++++++--------
 2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/arch/riscv/include/asm/ftrace.h b/arch/riscv/include/asm/ftrace.h
index c4721ce44ca47..ec6db1162021f 100644
--- a/arch/riscv/include/asm/ftrace.h
+++ b/arch/riscv/include/asm/ftrace.h
@@ -207,7 +207,7 @@ ftrace_partial_regs(const struct ftrace_regs *fregs, struct pt_regs *regs)
 {
 	struct __arch_ftrace_regs *afregs = arch_ftrace_regs(fregs);
 
-	memcpy(&regs->a0, afregs->args, sizeof(afregs->args));
+	memcpy(&regs->a_regs, afregs->args, sizeof(afregs->args));
 	regs->epc = afregs->epc;
 	regs->ra = afregs->ra;
 	regs->sp = afregs->sp;
diff --git a/arch/riscv/include/asm/ptrace.h b/arch/riscv/include/asm/ptrace.h
index b5b0adcc85c18..2910231977cb7 100644
--- a/arch/riscv/include/asm/ptrace.h
+++ b/arch/riscv/include/asm/ptrace.h
@@ -23,14 +23,16 @@ struct pt_regs {
 	unsigned long t2;
 	unsigned long s0;
 	unsigned long s1;
-	unsigned long a0;
-	unsigned long a1;
-	unsigned long a2;
-	unsigned long a3;
-	unsigned long a4;
-	unsigned long a5;
-	unsigned long a6;
-	unsigned long a7;
+	struct_group(a_regs,
+		unsigned long a0;
+		unsigned long a1;
+		unsigned long a2;
+		unsigned long a3;
+		unsigned long a4;
+		unsigned long a5;
+		unsigned long a6;
+		unsigned long a7;
+	);
 	unsigned long s2;
 	unsigned long s3;
 	unsigned long s4;
-- 
2.39.5

[PATCH AUTOSEL 6.14 8/9] tracing: Enforce the persistent ring buffer to be page aligned

[Sasha Levin]

From: Steven Rostedt <rostedt@goodmis.org>

[ Upstream commit c44a14f216f45d8bf1634b52854a699d7090f1e8 ]

Enforce that the address and the size of the memory used by the persistent
ring buffer is page aligned. Also update the documentation to reflect this
requirement.

Link: https://lore.kernel.org/all/CAHk-=whUOfVucfJRt7E0AH+GV41ELmS4wJqxHDnui6Giddfkzw@mail.gmail.com/

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Vincent Donnefort <vdonnefort@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Jann Horn <jannh@google.com>
Link: https://lore.kernel.org/20250402144953.412882844@goodmis.org
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 Documentation/admin-guide/kernel-parameters.txt |  2 ++
 Documentation/trace/debugging.rst               |  2 ++
 kernel/trace/trace.c                            | 10 ++++++++++
 3 files changed, 14 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index fb8752b42ec85..71861643ef143 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -7241,6 +7241,8 @@
 			This is just one of many ways that can clear memory. Make sure your system
 			keeps the content of memory across reboots before relying on this option.
 
+			NB: Both the mapped address and size must be page aligned for the architecture.
+
 			See also Documentation/trace/debugging.rst
 
 
diff --git a/Documentation/trace/debugging.rst b/Documentation/trace/debugging.rst
index 54fb16239d703..d54bc500af80b 100644
--- a/Documentation/trace/debugging.rst
+++ b/Documentation/trace/debugging.rst
@@ -136,6 +136,8 @@ kernel, so only the same kernel is guaranteed to work if the mapping is
 preserved. Switching to a different kernel version may find a different
 layout and mark the buffer as invalid.
 
+NB: Both the mapped address and size must be page aligned for the architecture.
+
 Using trace_printk() in the boot instance
 -----------------------------------------
 By default, the content of trace_printk() goes into the top level tracing
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 0e6d517e74e0f..50aa6d5908329 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -10427,6 +10427,16 @@ __init static void enable_instances(void)
 		}
 
 		if (start) {
+			/* Start and size must be page aligned */
+			if (start & ~PAGE_MASK) {
+				pr_warn("Tracing: mapping start addr %pa is not page aligned\n", &start);
+				continue;
+			}
+			if (size & ~PAGE_MASK) {
+				pr_warn("Tracing: mapping size %pa is not page aligned\n", &size);
+				continue;
+			}
+
 			addr = map_pages(start, size);
 			if (addr) {
 				pr_info("Tracing: mapped boot instance %s at physical memory %pa of size 0x%lx\n",
-- 
2.39.5