* [PATCH] arm64/efi: prefer AllocatePages() over efi_low_alloc() for vmlinux
@ 2015-07-24 9:41 Ard Biesheuvel
2015-07-24 10:49 ` Mark Rutland
0 siblings, 1 reply; 4+ messages in thread
From: Ard Biesheuvel @ 2015-07-24 9:41 UTC (permalink / raw)
To: linux-arm-kernel
When allocating memory for the kernel image, try the AllocatePages()
boot service to obtain memory at the preferred offset of
'dram_base + TEXT_OFFSET', and only revert to efi_low_alloc() if that
fails. This is the only way to allocate at the base of DRAM if DRAM
starts at 0x0, since efi_low_alloc() refuses to allocate at 0x0.
Tested-by: Haojian Zhuang <haojian.zhuang@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
arch/arm64/kernel/efi-stub.c | 47 ++++++++++++++++++++++++++++++++++++--------
1 file changed, 39 insertions(+), 8 deletions(-)
diff --git a/arch/arm64/kernel/efi-stub.c b/arch/arm64/kernel/efi-stub.c
index f5374065ad53..c8df74d14368 100644
--- a/arch/arm64/kernel/efi-stub.c
+++ b/arch/arm64/kernel/efi-stub.c
@@ -13,7 +13,7 @@
#include <asm/efi.h>
#include <asm/sections.h>
-efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table,
+efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table_arg,
unsigned long *image_addr,
unsigned long *image_size,
unsigned long *reserve_addr,
@@ -23,21 +23,52 @@ efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table,
{
efi_status_t status;
unsigned long kernel_size, kernel_memsize = 0;
+ unsigned long nr_pages;
/* Relocate the image, if required. */
kernel_size = _edata - _text;
if (*image_addr != (dram_base + TEXT_OFFSET)) {
kernel_memsize = kernel_size + (_end - _edata);
- status = efi_low_alloc(sys_table, kernel_memsize + TEXT_OFFSET,
- SZ_2M, reserve_addr);
+
+ //
+ // First, try a straight allocation at the preferred offset.
+ // This will work around the issue where, if dram_base == 0x0,
+ // efi_low_alloc() refuses to allocate at 0x0 (to prevent the
+ // address of the allocation to be mistaken for a FAIL return
+ // value or a NULL pointer). It will also ensure that, on
+ // platforms where the [dram_base, dram_base + TEXT_OFFSET)
+ // interval is partially occupied by the firmware (like on APM
+ // Mustang), we can still place the kernel at the address
+ // 'dram_base + TEXT_OFFSET'.
+ //
+ *reserve_addr = dram_base + TEXT_OFFSET;
+ nr_pages = round_up(kernel_memsize, EFI_ALLOC_ALIGN) /
+ EFI_PAGE_SIZE;
+ status = efi_call_early(allocate_pages, EFI_ALLOCATE_ADDRESS,
+ EFI_LOADER_DATA, nr_pages,
+ (efi_physical_addr_t *)reserve_addr);
+ if (status == EFI_SUCCESS) {
+ memcpy((void *)*reserve_addr, (void *)*image_addr,
+ kernel_size);
+ *image_addr = *reserve_addr;
+ *reserve_size = kernel_memsize;
+ } else {
+ status = efi_low_alloc(sys_table_arg,
+ kernel_memsize + TEXT_OFFSET,
+ SZ_2M, reserve_addr);
+
+ if (status == EFI_SUCCESS) {
+ memcpy((void *)*reserve_addr + TEXT_OFFSET,
+ (void *)*image_addr,
+ kernel_size);
+ *image_addr = *reserve_addr + TEXT_OFFSET;
+ *reserve_size = kernel_memsize + TEXT_OFFSET;
+ }
+ }
if (status != EFI_SUCCESS) {
- pr_efi_err(sys_table, "Failed to relocate kernel\n");
+ pr_efi_err(sys_table_arg, "Failed to relocate kernel\n");
return status;
}
- memcpy((void *)*reserve_addr + TEXT_OFFSET, (void *)*image_addr,
- kernel_size);
- *image_addr = *reserve_addr + TEXT_OFFSET;
- *reserve_size = kernel_memsize + TEXT_OFFSET;
}
--
1.9.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH] arm64/efi: prefer AllocatePages() over efi_low_alloc() for vmlinux
2015-07-24 9:41 [PATCH] arm64/efi: prefer AllocatePages() over efi_low_alloc() for vmlinux Ard Biesheuvel
@ 2015-07-24 10:49 ` Mark Rutland
2015-07-24 10:54 ` Ard Biesheuvel
0 siblings, 1 reply; 4+ messages in thread
From: Mark Rutland @ 2015-07-24 10:49 UTC (permalink / raw)
To: linux-arm-kernel
Hi Ard,
On Fri, Jul 24, 2015 at 10:41:53AM +0100, Ard Biesheuvel wrote:
> When allocating memory for the kernel image, try the AllocatePages()
> boot service to obtain memory at the preferred offset of
> 'dram_base + TEXT_OFFSET', and only revert to efi_low_alloc() if that
> fails. This is the only way to allocate at the base of DRAM if DRAM
> starts at 0x0, since efi_low_alloc() refuses to allocate at 0x0.
>
> Tested-by: Haojian Zhuang <haojian.zhuang@linaro.org>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
> arch/arm64/kernel/efi-stub.c | 47 ++++++++++++++++++++++++++++++++++++--------
> 1 file changed, 39 insertions(+), 8 deletions(-)
>
> diff --git a/arch/arm64/kernel/efi-stub.c b/arch/arm64/kernel/efi-stub.c
> index f5374065ad53..c8df74d14368 100644
> --- a/arch/arm64/kernel/efi-stub.c
> +++ b/arch/arm64/kernel/efi-stub.c
> @@ -13,7 +13,7 @@
> #include <asm/efi.h>
> #include <asm/sections.h>
>
> -efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table,
> +efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table_arg,
Any reason for the _arg addition?
> unsigned long *image_addr,
> unsigned long *image_size,
> unsigned long *reserve_addr,
> @@ -23,21 +23,52 @@ efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table,
> {
> efi_status_t status;
> unsigned long kernel_size, kernel_memsize = 0;
> + unsigned long nr_pages;
>
> /* Relocate the image, if required. */
> kernel_size = _edata - _text;
> if (*image_addr != (dram_base + TEXT_OFFSET)) {
> kernel_memsize = kernel_size + (_end - _edata);
> - status = efi_low_alloc(sys_table, kernel_memsize + TEXT_OFFSET,
> - SZ_2M, reserve_addr);
> +
> + //
> + // First, try a straight allocation at the preferred offset.
> + // This will work around the issue where, if dram_base == 0x0,
> + // efi_low_alloc() refuses to allocate at 0x0 (to prevent the
> + // address of the allocation to be mistaken for a FAIL return
> + // value or a NULL pointer). It will also ensure that, on
> + // platforms where the [dram_base, dram_base + TEXT_OFFSET)
> + // interval is partially occupied by the firmware (like on APM
> + // Mustang), we can still place the kernel at the address
> + // 'dram_base + TEXT_OFFSET'.
> + //
/*
* Nit: please use the standard comment style
*/
> + *reserve_addr = dram_base + TEXT_OFFSET;
> + nr_pages = round_up(kernel_memsize, EFI_ALLOC_ALIGN) /
> + EFI_PAGE_SIZE;
> + status = efi_call_early(allocate_pages, EFI_ALLOCATE_ADDRESS,
> + EFI_LOADER_DATA, nr_pages,
> + (efi_physical_addr_t *)reserve_addr);
> + if (status == EFI_SUCCESS) {
> + memcpy((void *)*reserve_addr, (void *)*image_addr,
> + kernel_size);
> + *image_addr = *reserve_addr;
> + *reserve_size = kernel_memsize;
> + } else {
> + status = efi_low_alloc(sys_table_arg,
> + kernel_memsize + TEXT_OFFSET,
> + SZ_2M, reserve_addr);
> +
> + if (status == EFI_SUCCESS) {
> + memcpy((void *)*reserve_addr + TEXT_OFFSET,
> + (void *)*image_addr,
> + kernel_size);
> + *image_addr = *reserve_addr + TEXT_OFFSET;
> + *reserve_size = kernel_memsize + TEXT_OFFSET;
> + }
> + }
> if (status != EFI_SUCCESS) {
> - pr_efi_err(sys_table, "Failed to relocate kernel\n");
> + pr_efi_err(sys_table_arg, "Failed to relocate kernel\n");
> return status;
> }
> - memcpy((void *)*reserve_addr + TEXT_OFFSET, (void *)*image_addr,
> - kernel_size);
Could we have a new_image_addr assigned in each case, and keep the
common memcpy here, followed by assignment to *image_addr? That would
save a couple of lines and guarantee the two cases stay in sync.
Otherwise this looks good to me.
Thanks,
Mark.
^ permalink raw reply [flat|nested] 4+ messages in thread* [PATCH] arm64/efi: prefer AllocatePages() over efi_low_alloc() for vmlinux
2015-07-24 10:49 ` Mark Rutland
@ 2015-07-24 10:54 ` Ard Biesheuvel
2015-07-24 10:59 ` Mark Rutland
0 siblings, 1 reply; 4+ messages in thread
From: Ard Biesheuvel @ 2015-07-24 10:54 UTC (permalink / raw)
To: linux-arm-kernel
On 24 July 2015 at 12:49, Mark Rutland <mark.rutland@arm.com> wrote:
> Hi Ard,
>
> On Fri, Jul 24, 2015 at 10:41:53AM +0100, Ard Biesheuvel wrote:
>> When allocating memory for the kernel image, try the AllocatePages()
>> boot service to obtain memory at the preferred offset of
>> 'dram_base + TEXT_OFFSET', and only revert to efi_low_alloc() if that
>> fails. This is the only way to allocate at the base of DRAM if DRAM
>> starts at 0x0, since efi_low_alloc() refuses to allocate at 0x0.
>>
>> Tested-by: Haojian Zhuang <haojian.zhuang@linaro.org>
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>> ---
>> arch/arm64/kernel/efi-stub.c | 47 ++++++++++++++++++++++++++++++++++++--------
>> 1 file changed, 39 insertions(+), 8 deletions(-)
>>
>> diff --git a/arch/arm64/kernel/efi-stub.c b/arch/arm64/kernel/efi-stub.c
>> index f5374065ad53..c8df74d14368 100644
>> --- a/arch/arm64/kernel/efi-stub.c
>> +++ b/arch/arm64/kernel/efi-stub.c
>> @@ -13,7 +13,7 @@
>> #include <asm/efi.h>
>> #include <asm/sections.h>
>>
>> -efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table,
>> +efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table_arg,
>
> Any reason for the _arg addition?
>
Yes. Unfortunately, the efi_call_early() macro has a hidden
'efi_system_table_t *' parameter which it refers to by the name
'sys_table_arg'
>> unsigned long *image_addr,
>> unsigned long *image_size,
>> unsigned long *reserve_addr,
>> @@ -23,21 +23,52 @@ efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table,
>> {
>> efi_status_t status;
>> unsigned long kernel_size, kernel_memsize = 0;
>> + unsigned long nr_pages;
>>
>> /* Relocate the image, if required. */
>> kernel_size = _edata - _text;
>> if (*image_addr != (dram_base + TEXT_OFFSET)) {
>> kernel_memsize = kernel_size + (_end - _edata);
>> - status = efi_low_alloc(sys_table, kernel_memsize + TEXT_OFFSET,
>> - SZ_2M, reserve_addr);
>> +
>> + //
>> + // First, try a straight allocation at the preferred offset.
>> + // This will work around the issue where, if dram_base == 0x0,
>> + // efi_low_alloc() refuses to allocate at 0x0 (to prevent the
>> + // address of the allocation to be mistaken for a FAIL return
>> + // value or a NULL pointer). It will also ensure that, on
>> + // platforms where the [dram_base, dram_base + TEXT_OFFSET)
>> + // interval is partially occupied by the firmware (like on APM
>> + // Mustang), we can still place the kernel at the address
>> + // 'dram_base + TEXT_OFFSET'.
>> + //
>
> /*
> * Nit: please use the standard comment style
> */
>
Absolutely. EDK2 development must be really screwing with my brain if
I am unconsciously using C++ style comments in C code. Time to move
back to the light side for a while :-)
>> + *reserve_addr = dram_base + TEXT_OFFSET;
>> + nr_pages = round_up(kernel_memsize, EFI_ALLOC_ALIGN) /
>> + EFI_PAGE_SIZE;
>> + status = efi_call_early(allocate_pages, EFI_ALLOCATE_ADDRESS,
>> + EFI_LOADER_DATA, nr_pages,
>> + (efi_physical_addr_t *)reserve_addr);
>> + if (status == EFI_SUCCESS) {
>> + memcpy((void *)*reserve_addr, (void *)*image_addr,
>> + kernel_size);
>> + *image_addr = *reserve_addr;
>> + *reserve_size = kernel_memsize;
>> + } else {
>> + status = efi_low_alloc(sys_table_arg,
>> + kernel_memsize + TEXT_OFFSET,
>> + SZ_2M, reserve_addr);
>> +
>> + if (status == EFI_SUCCESS) {
>> + memcpy((void *)*reserve_addr + TEXT_OFFSET,
>> + (void *)*image_addr,
>> + kernel_size);
>> + *image_addr = *reserve_addr + TEXT_OFFSET;
>> + *reserve_size = kernel_memsize + TEXT_OFFSET;
>> + }
>> + }
>> if (status != EFI_SUCCESS) {
>> - pr_efi_err(sys_table, "Failed to relocate kernel\n");
>> + pr_efi_err(sys_table_arg, "Failed to relocate kernel\n");
>> return status;
>> }
>> - memcpy((void *)*reserve_addr + TEXT_OFFSET, (void *)*image_addr,
>> - kernel_size);
>
> Could we have a new_image_addr assigned in each case, and keep the
> common memcpy here, followed by assignment to *image_addr? That would
> save a couple of lines and guarantee the two cases stay in sync.
>
Well, the memcpy() occurs before the assignment of *image_addr, which
is also used as the src arg. So I could record the value of
*image_addr in a temp, I suppose. I will do that in the next version.
> Otherwise this looks good to me.
>
Thanks,
Ard.
^ permalink raw reply [flat|nested] 4+ messages in thread* [PATCH] arm64/efi: prefer AllocatePages() over efi_low_alloc() for vmlinux
2015-07-24 10:54 ` Ard Biesheuvel
@ 2015-07-24 10:59 ` Mark Rutland
0 siblings, 0 replies; 4+ messages in thread
From: Mark Rutland @ 2015-07-24 10:59 UTC (permalink / raw)
To: linux-arm-kernel
On Fri, Jul 24, 2015 at 11:54:47AM +0100, Ard Biesheuvel wrote:
> On 24 July 2015 at 12:49, Mark Rutland <mark.rutland@arm.com> wrote:
> > Hi Ard,
> >
> > On Fri, Jul 24, 2015 at 10:41:53AM +0100, Ard Biesheuvel wrote:
> >> When allocating memory for the kernel image, try the AllocatePages()
> >> boot service to obtain memory at the preferred offset of
> >> 'dram_base + TEXT_OFFSET', and only revert to efi_low_alloc() if that
> >> fails. This is the only way to allocate at the base of DRAM if DRAM
> >> starts at 0x0, since efi_low_alloc() refuses to allocate at 0x0.
> >>
> >> Tested-by: Haojian Zhuang <haojian.zhuang@linaro.org>
> >> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> >> ---
> >> arch/arm64/kernel/efi-stub.c | 47 ++++++++++++++++++++++++++++++++++++--------
> >> 1 file changed, 39 insertions(+), 8 deletions(-)
> >>
> >> diff --git a/arch/arm64/kernel/efi-stub.c b/arch/arm64/kernel/efi-stub.c
> >> index f5374065ad53..c8df74d14368 100644
> >> --- a/arch/arm64/kernel/efi-stub.c
> >> +++ b/arch/arm64/kernel/efi-stub.c
> >> @@ -13,7 +13,7 @@
> >> #include <asm/efi.h>
> >> #include <asm/sections.h>
> >>
> >> -efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table,
> >> +efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table_arg,
> >
> > Any reason for the _arg addition?
> >
>
> Yes. Unfortunately, the efi_call_early() macro has a hidden
> 'efi_system_table_t *' parameter which it refers to by the name
> 'sys_table_arg'
Eww...
Ok, no worry.
> >> + *reserve_addr = dram_base + TEXT_OFFSET;
> >> + nr_pages = round_up(kernel_memsize, EFI_ALLOC_ALIGN) /
> >> + EFI_PAGE_SIZE;
> >> + status = efi_call_early(allocate_pages, EFI_ALLOCATE_ADDRESS,
> >> + EFI_LOADER_DATA, nr_pages,
> >> + (efi_physical_addr_t *)reserve_addr);
> >> + if (status == EFI_SUCCESS) {
> >> + memcpy((void *)*reserve_addr, (void *)*image_addr,
> >> + kernel_size);
> >> + *image_addr = *reserve_addr;
> >> + *reserve_size = kernel_memsize;
> >> + } else {
> >> + status = efi_low_alloc(sys_table_arg,
> >> + kernel_memsize + TEXT_OFFSET,
> >> + SZ_2M, reserve_addr);
> >> +
> >> + if (status == EFI_SUCCESS) {
> >> + memcpy((void *)*reserve_addr + TEXT_OFFSET,
> >> + (void *)*image_addr,
> >> + kernel_size);
> >> + *image_addr = *reserve_addr + TEXT_OFFSET;
> >> + *reserve_size = kernel_memsize + TEXT_OFFSET;
> >> + }
> >> + }
> >> if (status != EFI_SUCCESS) {
> >> - pr_efi_err(sys_table, "Failed to relocate kernel\n");
> >> + pr_efi_err(sys_table_arg, "Failed to relocate kernel\n");
> >> return status;
> >> }
> >> - memcpy((void *)*reserve_addr + TEXT_OFFSET, (void *)*image_addr,
> >> - kernel_size);
> >
> > Could we have a new_image_addr assigned in each case, and keep the
> > common memcpy here, followed by assignment to *image_addr? That would
> > save a couple of lines and guarantee the two cases stay in sync.
> >
>
> Well, the memcpy() occurs before the assignment of *image_addr, which
> is also used as the src arg. So I could record the value of
> *image_addr in a temp, I suppose. I will do that in the next version.
Yup, I suggested the name new_image_addr for said temporary ;)
Thanks,
Mark.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2015-07-24 9:41 [PATCH] arm64/efi: prefer AllocatePages() over efi_low_alloc() for vmlinux Ard Biesheuvel
2015-07-24 10:49 ` Mark Rutland
2015-07-24 10:54 ` Ard Biesheuvel
2015-07-24 10:59 ` Mark Rutland
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