[PATCH v1] drm/xe/sysctrl: Fix byte-order reversal in mailbox frame transport

["Anoop, Vijay" <anoop.c.vijay@intel.com>]

From: Anoop Vijay <anoop.c.vijay@intel.com>

sysctrl_write_frame()/sysctrl_read_frame() memcpy() mailbox payloads
into a u32 array before transferring them through the mailbox data
registers. This treats a little-endian byte stream as host-endian u32
values, causing word byte-swapping on big-endian systems.

Use get_unaligned_le32()/put_unaligned_le32() to convert each mailbox
word explicitly, preserving the little-endian wire format regardless
of host endianness.

Reported-by: Sashiko AI Reviewer <sashiko-bot@kernel.org>
Link: https://patchwork.freedesktop.org/patch/751309/?series=172513&rev=5
Signed-off-by: Anoop Vijay <anoop.c.vijay@intel.com>
---
 drivers/gpu/drm/xe/xe_sysctrl_mailbox.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_sysctrl_mailbox.c b/drivers/gpu/drm/xe/xe_sysctrl_mailbox.c
index 72baf1aa4b3a..d5a34a24a0d6 100644
--- a/drivers/gpu/drm/xe/xe_sysctrl_mailbox.c
+++ b/drivers/gpu/drm/xe/xe_sysctrl_mailbox.c
@@ -8,6 +8,7 @@
 #include <linux/minmax.h>
 #include <linux/slab.h>
 #include <linux/string.h>
+#include <linux/unaligned.h>
 
 #include "regs/xe_sysctrl_regs.h"
 #include "xe_device.h"
@@ -63,16 +64,16 @@ static int sysctrl_write_frame(struct xe_sysctrl *sc, const void *frame,
 		SYSCTRL_MB_DATA0, SYSCTRL_MB_DATA1, SYSCTRL_MB_DATA2, SYSCTRL_MB_DATA3
 	};
 	struct xe_device *xe = sc_to_xe(sc);
-	u32 val[XE_SYSCTRL_MB_FRAME_SIZE / sizeof(u32)] = {0};
+	u8 buf[XE_SYSCTRL_MB_FRAME_SIZE] = {};
 	u32 dw = DIV_ROUND_UP(len, sizeof(u32));
 	u32 i;
 
 	xe_assert(xe, len > 0 && len <= XE_SYSCTRL_MB_FRAME_SIZE);
 
-	memcpy(val, frame, len);
+	memcpy(buf, frame, len);
 
 	for (i = 0; i < dw; i++)
-		xe_mmio_write32(sc->mmio, regs[i], val[i]);
+		xe_mmio_write32(sc->mmio, regs[i], get_unaligned_le32(buf + i * sizeof(u32)));
 
 	return 0;
 }
@@ -84,16 +85,16 @@ static int sysctrl_read_frame(struct xe_sysctrl *sc, void *frame,
 		SYSCTRL_MB_DATA0, SYSCTRL_MB_DATA1, SYSCTRL_MB_DATA2, SYSCTRL_MB_DATA3
 	};
 	struct xe_device *xe = sc_to_xe(sc);
-	u32 val[XE_SYSCTRL_MB_FRAME_SIZE / sizeof(u32)] = {0};
+	u8 buf[XE_SYSCTRL_MB_FRAME_SIZE] = {};
 	u32 dw = DIV_ROUND_UP(len, sizeof(u32));
 	u32 i;
 
 	xe_assert(xe, len > 0 && len <= XE_SYSCTRL_MB_FRAME_SIZE);
 
 	for (i = 0; i < dw; i++)
-		val[i] = xe_mmio_read32(sc->mmio, regs[i]);
+		put_unaligned_le32(xe_mmio_read32(sc->mmio, regs[i]), buf + i * sizeof(u32));
 
-	memcpy(frame, val, len);
+	memcpy(frame, buf, len);
 
 	return 0;
 }
-- 
2.43.0