In a EFI system, the frame buffer address is 64bit, so currently
if the address is beyound 4G, kexec will set wrong address due to
truncate.
Linux kernel commit ae2ee627dc87 ('efifb: Add support for 64-bit
frame buffer addresses') added support for 64bit frame buffer
address, an 'ext_lfb_base' field is added as the upper 32-bits of
the frame buffer, and introduced a new capability flag
'VIDEO_TYPE_CAPABILITY_64BIT_BASE' to indicate if the extend field is
used.
This patch adopts this change, set proper extent address and capability
flag when the address is beyound 4G.
Signed-off-by: Kairui Song <kasong@xxxxxxxxxx>
---
Update from V1:
- Use 0xffffffffUL instead of 0xffffffff for comparing and bit operation
with smem_start to make it cleaner and safer, as smem_start is an
unsigned long.
include/x86/x86-linux.h | 7 +++++--
kexec/arch/i386/x86-linux-setup.c | 7 ++++++-
2 files changed, 11 insertions(+), 3 deletions(-)
diff --git a/include/x86/x86-linux.h b/include/x86/x86-linux.h
index 7834751..352ea02 100644
--- a/include/x86/x86-linux.h
+++ b/include/x86/x86-linux.h
@@ -107,7 +107,10 @@ struct x86_linux_param_header {
uint16_t vesapm_seg; /* 0x2e */
uint16_t vesapm_off; /* 0x30 */
uint16_t pages; /* 0x32 */
- uint8_t reserved4[12]; /* 0x34 -- 0x3f reserved for future expansion */
+ uint16_t vesa_attributes; /* 0x34 */
+ uint32_t capabilities; /* 0x36 */
+ uint32_t ext_lfb_base; /* 0x3a */
+ uint8_t reserved4[2]; /* 0x3e -- 0x3f reserved for future expansion */
struct apm_bios_info apm_bios_info; /* 0x40 */
struct drive_info_struct drive_info; /* 0x80 */
@@ -199,7 +202,7 @@ struct x86_linux_param_header {
struct edd_info eddbuf[EDDMAXNR]; /* 0xd00 */
/* 0xeec */
#define COMMAND_LINE_SIZE 2048
-};
+} __attribute__((packed));
struct x86_linux_faked_param_header {
struct x86_linux_param_header hdr; /* 0x00 */
diff --git a/kexec/arch/i386/x86-linux-setup.c b/kexec/arch/i386/x86-linux-setup.c
index 6cda12c..1bd408b 100644
--- a/kexec/arch/i386/x86-linux-setup.c
+++ b/kexec/arch/i386/x86-linux-setup.c
@@ -158,10 +158,15 @@ static int setup_linux_vesafb(struct x86_linux_param_header *real_mode)
real_mode->lfb_width = var.xres;
real_mode->lfb_height = var.yres;
real_mode->lfb_depth = var.bits_per_pixel;
- real_mode->lfb_base = fix.smem_start;
+ real_mode->lfb_base = fix.smem_start & 0xffffffffUL;
real_mode->lfb_linelength = fix.line_length;
real_mode->vesapm_seg = 0;
+ if (fix.smem_start > 0xffffffffUL) {
+ real_mode->ext_lfb_base = fix.smem_start >> 32;
+ real_mode->capabilities |= VIDEO_CAPABILITY_64BIT_BASE;
+ }
+
/* FIXME: better get size from the file returned by proc_iomem() */
real_mode->lfb_size = (fix.smem_len + 65535) / 65536;
real_mode->pages = (fix.smem_len + 4095) / 4096;
--
2.19.1
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