[PATCH] x86/boot/compressed: Fix signedness of rdfs8()

[redacherkaoui]

rdfs8() reads a raw byte from the decompressor command line buffer but
returns it as 'char'. On toolchains where 'char' is signed, values in
the range 0x80..0xff become negative when promoted, which can lead to
incorrect comparisons while parsing.

Return u8 from rdfs8() to preserve the correct byte value.

Signed-off-by: redacherkaoui <redacherkaoui67@xxxxxxxxx>
---
 arch/x86/boot/compressed/cmdline.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/x86/boot/compressed/cmdline.c b/arch/x86/boot/compressed/cmdline.c
index e162d7f59cc5..d48ba959dbc5 100644
--- a/arch/x86/boot/compressed/cmdline.c
+++ b/arch/x86/boot/compressed/cmdline.c
@@ -8,13 +8,16 @@ static inline void set_fs(unsigned long seg)
 {
 	fs = seg << 4;  /* shift it back */
 }
+
 typedef unsigned long addr_t;
-static inline char rdfs8(addr_t addr)
+static inline u8 rdfs8(addr_t addr)
 {
-	return *((char *)(fs + addr));
+	return *(u8 *)(fs + addr);
 }
+
 #include "../cmdline.c"
-unsigned long get_cmd_line_ptr(void)
+
+static unsigned long get_cmd_line_ptr(void)
 {
 	unsigned long cmd_line_ptr = boot_params_ptr->hdr.cmd_line_ptr;
 
@@ -22,10 +25,12 @@ unsigned long get_cmd_line_ptr(void)
 
 	return cmd_line_ptr;
 }
+
 int cmdline_find_option(const char *option, char *buffer, int bufsize)
 {
 	return __cmdline_find_option(get_cmd_line_ptr(), option, buffer, bufsize);
 }
+
 int cmdline_find_option_bool(const char *option)
 {
 	return __cmdline_find_option_bool(get_cmd_line_ptr(), option);
-- 
2.43.0