[v2,6/6] x86/boot: Use boot_vid_info variable directly from C code

Commit Message

Frediano Ziglio Oct. 7, 2024, 2:15 p.m. UTC

No more need to pass from assembly code.

Signed-off-by: Frediano Ziglio <[e-mail]>
---
 xen/arch/x86/boot/build32.lds.S |  1 +
 xen/arch/x86/boot/head.S        |  9 +--------
 xen/arch/x86/boot/reloc.c       | 12 +++++-------
 3 files changed, 7 insertions(+), 15 deletions(-)

Comments

Andrew Cooper Oct. 10, 2024, 1:02 p.m. UTC | #1

On 07/10/2024 3:15 pm, Frediano Ziglio wrote:
> No more need to pass from assembly code.
>
> Signed-off-by: Frediano Ziglio <[e-mail]>

This patch is fine now.

As noted in patch 5, there will be less net churn if the order was
swapped.  (As it stands, there's at least one correction in this patch
as a knock-on effect.)

~Andrew

Patch

diff --git a/xen/arch/x86/boot/build32.lds.S b/xen/arch/x86/boot/build32.lds.S
index 9d09e3adbd..26ef609523 100644
--- a/xen/arch/x86/boot/build32.lds.S
+++ b/xen/arch/x86/boot/build32.lds.S
@@ -46,6 +46,7 @@  SECTIONS
         DECLARE_IMPORT(__trampoline_seg_start);
         DECLARE_IMPORT(__trampoline_seg_stop);
         DECLARE_IMPORT(trampoline_phys);
+        DECLARE_IMPORT(boot_vid_info);
         . = . + GAP;
         *(.text)
         *(.text.*)
diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S
index 32b658fa2b..dcda91cfda 100644
--- a/xen/arch/x86/boot/head.S
+++ b/xen/arch/x86/boot/head.S
@@ -510,16 +510,9 @@  trampoline_setup:
         mov     %esi, sym_esi(xen_phys_start)
         mov     %esi, sym_esi(trampoline_xen_phys_start)
 
-        /* Boot video info to be filled from MB2. */
-#ifdef CONFIG_VIDEO
-        lea     sym_esi(boot_vid_info), %ecx
-#else
-        xor     %ecx, %ecx
-#endif
-
         /* Save Multiboot / PVH info struct (after relocation) for later use. */
         mov     %ebx, %edx          /* Multiboot / PVH information address. */
-        /*      reloc(magic/eax, info/edx, video/stk) using fastcall. */
+        /*      reloc(magic/eax, info/edx) using fastcall. */
         call    reloc
 
 #ifdef CONFIG_PVH_GUEST
diff --git a/xen/arch/x86/boot/reloc.c b/xen/arch/x86/boot/reloc.c
index 4cca61adec..8527fa8d01 100644
--- a/xen/arch/x86/boot/reloc.c
+++ b/xen/arch/x86/boot/reloc.c
@@ -179,7 +179,7 @@  static multiboot_info_t *mbi_reloc(uint32_t mbi_in, memctx *ctx)
     return mbi_out;
 }
 
-static multiboot_info_t *mbi2_reloc(uint32_t mbi_in, uint32_t video_out, memctx *ctx)
+static multiboot_info_t *mbi2_reloc(uint32_t mbi_in, memctx *ctx)
 {
     const multiboot2_fixed_t *mbi_fix = _p(mbi_in);
     const multiboot2_memory_map_t *mmap_src;
@@ -188,7 +188,7 @@  static multiboot_info_t *mbi2_reloc(uint32_t mbi_in, uint32_t video_out, memctx
     memory_map_t *mmap_dst;
     multiboot_info_t *mbi_out;
 #ifdef CONFIG_VIDEO
-    struct boot_video_info *video = NULL;
+    struct boot_video_info *video = &boot_vid_info;
 #endif
     uint32_t ptr;
     unsigned int i, mod_idx = 0;
@@ -293,12 +293,11 @@  static multiboot_info_t *mbi2_reloc(uint32_t mbi_in, uint32_t video_out, memctx
 
 #ifdef CONFIG_VIDEO
         case MULTIBOOT2_TAG_TYPE_VBE:
-            if ( video_out )
+            if ( video )
             {
                 const struct vesa_ctrl_info *ci;
                 const struct vesa_mode_info *mi;
 
-                video = _p(video_out);
                 ci = (const void *)get_mb2_data(tag, vbe, vbe_control_info);
                 mi = (const void *)get_mb2_data(tag, vbe, vbe_mode_info);
 
@@ -324,7 +323,6 @@  static multiboot_info_t *mbi2_reloc(uint32_t mbi_in, uint32_t video_out, memctx
             if ( (get_mb2_data(tag, framebuffer, framebuffer_type) !=
                   MULTIBOOT2_FRAMEBUFFER_TYPE_RGB) )
             {
-                video_out = 0;
                 video = NULL;
             }
             break;
@@ -349,7 +347,7 @@  static multiboot_info_t *mbi2_reloc(uint32_t mbi_in, uint32_t video_out, memctx
 }
 
 /* SAF-1-safe */
-void *reloc(uint32_t magic, uint32_t in, uint32_t video_info)
+void *reloc(uint32_t magic, uint32_t in)
 {
     /* Get bottom-most low-memory stack address. */
     memctx ctx = { (uint32_t)((long)trampoline_phys + TRAMPOLINE_SPACE) };
@@ -360,7 +358,7 @@  void *reloc(uint32_t magic, uint32_t in, uint32_t video_info)
         return mbi_reloc(in, &ctx);
 
     case MULTIBOOT2_BOOTLOADER_MAGIC:
-        return mbi2_reloc(in, video_info, &ctx);
+        return mbi2_reloc(in, &ctx);
 
     case XEN_HVM_START_MAGIC_VALUE:
         if ( IS_ENABLED(CONFIG_PVH_GUEST) )