[PATCH] x86: Handle 64bit framebuffer memory address properly

[PATCH] x86: Handle 64bit framebuffer memory address properly

[Kairui Song]

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@redhat.com>
---
 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..dc785a2 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 & 0xffffffff;
 	real_mode->lfb_linelength = fix.line_length;
 	real_mode->vesapm_seg     = 0;
 
+	if (fix.smem_start > 0xffffffff) {
+		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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Re: [PATCH] x86: Handle 64bit framebuffer memory address properly

[Dave Young]

Hi Kairui,

On 11/23/18 at 05:26pm, Kairui Song wrote:
> 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@redhat.com>
> ---
>  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..dc785a2 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 & 0xffffffff;
>  	real_mode->lfb_linelength = fix.line_length;
>  	real_mode->vesapm_seg     = 0;
>  
> +	if (fix.smem_start > 0xffffffff) {

This might be a problem for 32 bit case?  Other than this I do not see
other issues of this patch.

> +		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
> 
> 
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec

Thanks
Dave

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Re: [PATCH] x86: Handle 64bit framebuffer memory address properly

[Kairui Song]

Hi Dave, thanks for the review.
It should be safe, "smem_start" is defined as an unsigned long and with 32bit
it will always smaller than 0xffffffff, but to make it cleaner and
safer I will update the
patch to use 0xffffffffUL instead.
On Tue, Dec 4, 2018 at 7:50 PM Dave Young <dyoung@redhat.com> wrote:
>
> Hi Kairui,
>
> On 11/23/18 at 05:26pm, Kairui Song wrote:
> > 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@redhat.com>
> > ---
> >  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..dc785a2 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 & 0xffffffff;
> >       real_mode->lfb_linelength = fix.line_length;
> >       real_mode->vesapm_seg     = 0;
> >
> > +     if (fix.smem_start > 0xffffffff) {
>
> This might be a problem for 32 bit case?  Other than this I do not see
> other issues of this patch.
>
> > +             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
> >
> >
> > _______________________________________________
> > kexec mailing list
> > kexec@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/kexec
>
> Thanks
> Dave



-- 
Best Regards,
Kairui Song

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Re: [PATCH] x86: Handle 64bit framebuffer memory address properly

[Simon Horman]

On Fri, Nov 23, 2018 at 05:26:33PM +0800, Kairui Song wrote:
> 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@redhat.com>

Sorry for letting this slip through the cracks.
Please let me know if this is still relevant.

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Re: [PATCH] x86: Handle 64bit framebuffer memory address properly

[Kairui Song]

On Fri, May 31, 2019 at 5:29 PM Simon Horman <horms@verge.net.au> wrote:
>
> On Fri, Nov 23, 2018 at 05:26:33PM +0800, Kairui Song wrote:
> > 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@redhat.com>
>
> Sorry for letting this slip through the cracks.
> Please let me know if this is still relevant.

Hi Simon, I checked kexec-tools repo and this patch is merged already,
maybe you replied the wrong mail?


--
Best Regards,
Kairui Song

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