[xen staging] xen/video: CFI hardening

[patchbot@xxxxxxx]

commit 17a69ac9d1e59fda240f996a27440d324bf020f8
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Fri Oct 29 19:41:13 2021 +0100
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Wed Feb 23 15:33:43 2022 +0000

    xen/video: CFI hardening
    
    Control Flow Integrity schemes use toolchain and optionally hardware support
    to help protect against call/jump/return oriented programming attacks.
    
    Use cf_check to annotate function pointer targets for the toolchain.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/drivers/video/lfb.c  | 4 ++--
 xen/drivers/video/lfb.h  | 4 ++--
 xen/drivers/video/vesa.c | 4 ++--
 xen/drivers/video/vga.c  | 6 +++---
 4 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/xen/drivers/video/lfb.c b/xen/drivers/video/lfb.c
index 9254b5e902..a6fb837974 100644
--- a/xen/drivers/video/lfb.c
+++ b/xen/drivers/video/lfb.c
@@ -53,7 +53,7 @@ static void lfb_show_line(
 }
 
 /* Fast mode which redraws all modified parts of a 2D text buffer. */
-void lfb_redraw_puts(const char *s, size_t nr)
+void cf_check lfb_redraw_puts(const char *s, size_t nr)
 {
     unsigned int i, min_redraw_y = lfb.ypos;
 
@@ -98,7 +98,7 @@ void lfb_redraw_puts(const char *s, size_t nr)
 }
 
 /* Slower line-based scroll mode which interacts better with dom0. */
-void lfb_scroll_puts(const char *s, size_t nr)
+void cf_check lfb_scroll_puts(const char *s, size_t nr)
 {
     unsigned int i;
 
diff --git a/xen/drivers/video/lfb.h b/xen/drivers/video/lfb.h
index e743ccdd6b..42161402d6 100644
--- a/xen/drivers/video/lfb.h
+++ b/xen/drivers/video/lfb.h
@@ -35,8 +35,8 @@ struct lfb_prop {
     unsigned int text_rows;
 };
 
-void lfb_redraw_puts(const char *s, size_t nr);
-void lfb_scroll_puts(const char *s, size_t nr);
+void cf_check lfb_redraw_puts(const char *s, size_t nr);
+void cf_check lfb_scroll_puts(const char *s, size_t nr);
 void lfb_carriage_return(void);
 void lfb_free(void);
 
diff --git a/xen/drivers/video/vesa.c b/xen/drivers/video/vesa.c
index c8f81a5cc5..c41f6b8d40 100644
--- a/xen/drivers/video/vesa.c
+++ b/xen/drivers/video/vesa.c
@@ -17,7 +17,7 @@
 
 #define vlfb_info    vga_console_info.u.vesa_lfb
 
-static void lfb_flush(void);
+static void cf_check lfb_flush(void);
 
 static unsigned char *__read_mostly lfb;
 static const struct font_desc *__initdata font;
@@ -140,7 +140,7 @@ void __init vesa_init(void)
     video_puts = lfb_redraw_puts;
 }
 
-static void lfb_flush(void)
+static void cf_check lfb_flush(void)
 {
     __asm__ __volatile__ ("sfence" : : : "memory");
 }
diff --git a/xen/drivers/video/vga.c b/xen/drivers/video/vga.c
index 5e58f83c97..e624ebff4f 100644
--- a/xen/drivers/video/vga.c
+++ b/xen/drivers/video/vga.c
@@ -19,8 +19,8 @@ static int vgacon_keep;
 static unsigned int xpos, ypos;
 static unsigned char *video;
 
-static void vga_text_puts(const char *s, size_t nr);
-static void vga_noop_puts(const char *s, size_t nr) {}
+static void cf_check vga_text_puts(const char *s, size_t nr);
+static void cf_check vga_noop_puts(const char *s, size_t nr) {}
 void (*video_puts)(const char *, size_t nr) = vga_noop_puts;
 
 /*
@@ -179,7 +179,7 @@ void __init video_endboot(void)
     }
 }
 
-static void vga_text_puts(const char *s, size_t nr)
+static void cf_check vga_text_puts(const char *s, size_t nr)
 {
     for ( ; nr > 0; nr--, s++ )
     {
--
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