* [PATCH] efi/memreserve: deal with memreserve entries in unmapped memory
@ 2019-06-10 15:05 ` Ard Biesheuvel
0 siblings, 0 replies; 6+ messages in thread
From: Ard Biesheuvel @ 2019-06-10 15:05 UTC (permalink / raw)
To: linux-efi
Cc: linux-arm-kernel, marc.zyngier, bhsharma, ray.jui,
Ard Biesheuvel, Jonathan Richardson
Ensure that the EFI memreserve entries can be accessed, even if they
are located in memory that the kernel (e.g., a crashkernel) omits from
the linear map.
Reported-by: Jonathan Richardson <jonathan.richardson@broadcom.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
drivers/firmware/efi/efi.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 16b2137d117c..4b7cf7bc0ded 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -1009,14 +1009,16 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
/* first try to find a slot in an existing linked list entry */
for (prsv = efi_memreserve_root->next; prsv; prsv = rsv->next) {
- rsv = __va(prsv);
+ rsv = memremap(prsv, sizeof(*rsv), MEMREMAP_WB);
index = atomic_fetch_add_unless(&rsv->count, 1, rsv->size);
if (index < rsv->size) {
rsv->entry[index].base = addr;
rsv->entry[index].size = size;
+ memunmap(rsv);
return 0;
}
+ memunmap(rsv);
}
/* no slot found - allocate a new linked list entry */
@@ -1024,7 +1026,13 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
if (!rsv)
return -ENOMEM;
- rsv->size = EFI_MEMRESERVE_COUNT(PAGE_SIZE);
+ /*
+ * The memremap() call above assumes that a linux_efi_memreserve entry
+ * never crosses a page boundary, so let's ensure that this remains true
+ * even when kexec'ing a 4k pages kernel from a >4k pages kernel, by
+ * using SZ_4K explicitly in the size calculation below.
+ */
+ rsv->size = EFI_MEMRESERVE_COUNT(SZ_4K);
atomic_set(&rsv->count, 1);
rsv->entry[0].base = addr;
rsv->entry[0].size = size;
--
2.20.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH] efi/memreserve: deal with memreserve entries in unmapped memory
@ 2019-06-10 15:05 ` Ard Biesheuvel
0 siblings, 0 replies; 6+ messages in thread
From: Ard Biesheuvel @ 2019-06-10 15:05 UTC (permalink / raw)
To: linux-efi
Cc: Jonathan Richardson, Ard Biesheuvel, marc.zyngier, bhsharma,
ray.jui, linux-arm-kernel
Ensure that the EFI memreserve entries can be accessed, even if they
are located in memory that the kernel (e.g., a crashkernel) omits from
the linear map.
Reported-by: Jonathan Richardson <jonathan.richardson@broadcom.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
drivers/firmware/efi/efi.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 16b2137d117c..4b7cf7bc0ded 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -1009,14 +1009,16 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
/* first try to find a slot in an existing linked list entry */
for (prsv = efi_memreserve_root->next; prsv; prsv = rsv->next) {
- rsv = __va(prsv);
+ rsv = memremap(prsv, sizeof(*rsv), MEMREMAP_WB);
index = atomic_fetch_add_unless(&rsv->count, 1, rsv->size);
if (index < rsv->size) {
rsv->entry[index].base = addr;
rsv->entry[index].size = size;
+ memunmap(rsv);
return 0;
}
+ memunmap(rsv);
}
/* no slot found - allocate a new linked list entry */
@@ -1024,7 +1026,13 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
if (!rsv)
return -ENOMEM;
- rsv->size = EFI_MEMRESERVE_COUNT(PAGE_SIZE);
+ /*
+ * The memremap() call above assumes that a linux_efi_memreserve entry
+ * never crosses a page boundary, so let's ensure that this remains true
+ * even when kexec'ing a 4k pages kernel from a >4k pages kernel, by
+ * using SZ_4K explicitly in the size calculation below.
+ */
+ rsv->size = EFI_MEMRESERVE_COUNT(SZ_4K);
atomic_set(&rsv->count, 1);
rsv->entry[0].base = addr;
rsv->entry[0].size = size;
--
2.20.1
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] efi/memreserve: deal with memreserve entries in unmapped memory
2019-06-10 15:05 ` Ard Biesheuvel
@ 2019-06-10 16:27 ` Ray Jui
-1 siblings, 0 replies; 6+ messages in thread
From: Ray Jui @ 2019-06-10 16:27 UTC (permalink / raw)
To: Ard Biesheuvel, linux-efi
Cc: linux-arm-kernel, marc.zyngier, bhsharma, Jonathan Richardson
Hi Ard,
On 6/10/2019 8:05 AM, Ard Biesheuvel wrote:
> Ensure that the EFI memreserve entries can be accessed, even if they
> are located in memory that the kernel (e.g., a crashkernel) omits from
> the linear map.
>
> Reported-by: Jonathan Richardson <jonathan.richardson@broadcom.com>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Does it make sense to add a Fixes tag?
> ---
> drivers/firmware/efi/efi.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index 16b2137d117c..4b7cf7bc0ded 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -1009,14 +1009,16 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
>
> /* first try to find a slot in an existing linked list entry */
> for (prsv = efi_memreserve_root->next; prsv; prsv = rsv->next) {
> - rsv = __va(prsv);
> + rsv = memremap(prsv, sizeof(*rsv), MEMREMAP_WB);
> index = atomic_fetch_add_unless(&rsv->count, 1, rsv->size);
> if (index < rsv->size) {
> rsv->entry[index].base = addr;
> rsv->entry[index].size = size;
>
> + memunmap(rsv);
> return 0;
> }
> + memunmap(rsv);
> }
>
> /* no slot found - allocate a new linked list entry */
> @@ -1024,7 +1026,13 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
> if (!rsv)
> return -ENOMEM;
>
> - rsv->size = EFI_MEMRESERVE_COUNT(PAGE_SIZE);
> + /*
> + * The memremap() call above assumes that a linux_efi_memreserve entry
> + * never crosses a page boundary, so let's ensure that this remains true
> + * even when kexec'ing a 4k pages kernel from a >4k pages kernel, by
> + * using SZ_4K explicitly in the size calculation below.
> + */
> + rsv->size = EFI_MEMRESERVE_COUNT(SZ_4K);
> atomic_set(&rsv->count, 1);
> rsv->entry[0].base = addr;
> rsv->entry[0].size = size;
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] efi/memreserve: deal with memreserve entries in unmapped memory
@ 2019-06-10 16:27 ` Ray Jui
0 siblings, 0 replies; 6+ messages in thread
From: Ray Jui @ 2019-06-10 16:27 UTC (permalink / raw)
To: Ard Biesheuvel, linux-efi
Cc: marc.zyngier, bhsharma, Jonathan Richardson, linux-arm-kernel
Hi Ard,
On 6/10/2019 8:05 AM, Ard Biesheuvel wrote:
> Ensure that the EFI memreserve entries can be accessed, even if they
> are located in memory that the kernel (e.g., a crashkernel) omits from
> the linear map.
>
> Reported-by: Jonathan Richardson <jonathan.richardson@broadcom.com>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Does it make sense to add a Fixes tag?
> ---
> drivers/firmware/efi/efi.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index 16b2137d117c..4b7cf7bc0ded 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -1009,14 +1009,16 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
>
> /* first try to find a slot in an existing linked list entry */
> for (prsv = efi_memreserve_root->next; prsv; prsv = rsv->next) {
> - rsv = __va(prsv);
> + rsv = memremap(prsv, sizeof(*rsv), MEMREMAP_WB);
> index = atomic_fetch_add_unless(&rsv->count, 1, rsv->size);
> if (index < rsv->size) {
> rsv->entry[index].base = addr;
> rsv->entry[index].size = size;
>
> + memunmap(rsv);
> return 0;
> }
> + memunmap(rsv);
> }
>
> /* no slot found - allocate a new linked list entry */
> @@ -1024,7 +1026,13 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
> if (!rsv)
> return -ENOMEM;
>
> - rsv->size = EFI_MEMRESERVE_COUNT(PAGE_SIZE);
> + /*
> + * The memremap() call above assumes that a linux_efi_memreserve entry
> + * never crosses a page boundary, so let's ensure that this remains true
> + * even when kexec'ing a 4k pages kernel from a >4k pages kernel, by
> + * using SZ_4K explicitly in the size calculation below.
> + */
> + rsv->size = EFI_MEMRESERVE_COUNT(SZ_4K);
> atomic_set(&rsv->count, 1);
> rsv->entry[0].base = addr;
> rsv->entry[0].size = size;
>
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] efi/memreserve: deal with memreserve entries in unmapped memory
2019-06-10 15:05 ` Ard Biesheuvel
@ 2019-06-11 1:00 ` Jonathan Richardson
-1 siblings, 0 replies; 6+ messages in thread
From: Jonathan Richardson @ 2019-06-11 1:00 UTC (permalink / raw)
To: Ard Biesheuvel, linux-efi
Cc: linux-arm-kernel, marc.zyngier, bhsharma, ray.jui
On 06/10/2019 08:05 AM, Ard Biesheuvel wrote:
> Ensure that the EFI memreserve entries can be accessed, even if they
> are located in memory that the kernel (e.g., a crashkernel) omits from
> the linear map.
>
> Reported-by: Jonathan Richardson <jonathan.richardson@broadcom.com>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
> drivers/firmware/efi/efi.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index 16b2137d117c..4b7cf7bc0ded 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -1009,14 +1009,16 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
>
> /* first try to find a slot in an existing linked list entry */
> for (prsv = efi_memreserve_root->next; prsv; prsv = rsv->next) {
> - rsv = __va(prsv);
> + rsv = memremap(prsv, sizeof(*rsv), MEMREMAP_WB);
> index = atomic_fetch_add_unless(&rsv->count, 1, rsv->size);
> if (index < rsv->size) {
> rsv->entry[index].base = addr;
> rsv->entry[index].size = size;
>
> + memunmap(rsv);
> return 0;
> }
> + memunmap(rsv);
> }
>
> /* no slot found - allocate a new linked list entry */
> @@ -1024,7 +1026,13 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
> if (!rsv)
> return -ENOMEM;
>
> - rsv->size = EFI_MEMRESERVE_COUNT(PAGE_SIZE);
> + /*
> + * The memremap() call above assumes that a linux_efi_memreserve entry
> + * never crosses a page boundary, so let's ensure that this remains true
> + * even when kexec'ing a 4k pages kernel from a >4k pages kernel, by
> + * using SZ_4K explicitly in the size calculation below.
> + */
> + rsv->size = EFI_MEMRESERVE_COUNT(SZ_4K);
> atomic_set(&rsv->count, 1);
> rsv->entry[0].base = addr;
> rsv->entry[0].size = size;
>
Thanks for the fix. Tested and reviewed.
Reviewed-by: Jonathan Richardson <jonathan.richardson@broadcom.com>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] efi/memreserve: deal with memreserve entries in unmapped memory
@ 2019-06-11 1:00 ` Jonathan Richardson
0 siblings, 0 replies; 6+ messages in thread
From: Jonathan Richardson @ 2019-06-11 1:00 UTC (permalink / raw)
To: Ard Biesheuvel, linux-efi
Cc: marc.zyngier, bhsharma, ray.jui, linux-arm-kernel
On 06/10/2019 08:05 AM, Ard Biesheuvel wrote:
> Ensure that the EFI memreserve entries can be accessed, even if they
> are located in memory that the kernel (e.g., a crashkernel) omits from
> the linear map.
>
> Reported-by: Jonathan Richardson <jonathan.richardson@broadcom.com>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
> drivers/firmware/efi/efi.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index 16b2137d117c..4b7cf7bc0ded 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -1009,14 +1009,16 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
>
> /* first try to find a slot in an existing linked list entry */
> for (prsv = efi_memreserve_root->next; prsv; prsv = rsv->next) {
> - rsv = __va(prsv);
> + rsv = memremap(prsv, sizeof(*rsv), MEMREMAP_WB);
> index = atomic_fetch_add_unless(&rsv->count, 1, rsv->size);
> if (index < rsv->size) {
> rsv->entry[index].base = addr;
> rsv->entry[index].size = size;
>
> + memunmap(rsv);
> return 0;
> }
> + memunmap(rsv);
> }
>
> /* no slot found - allocate a new linked list entry */
> @@ -1024,7 +1026,13 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
> if (!rsv)
> return -ENOMEM;
>
> - rsv->size = EFI_MEMRESERVE_COUNT(PAGE_SIZE);
> + /*
> + * The memremap() call above assumes that a linux_efi_memreserve entry
> + * never crosses a page boundary, so let's ensure that this remains true
> + * even when kexec'ing a 4k pages kernel from a >4k pages kernel, by
> + * using SZ_4K explicitly in the size calculation below.
> + */
> + rsv->size = EFI_MEMRESERVE_COUNT(SZ_4K);
> atomic_set(&rsv->count, 1);
> rsv->entry[0].base = addr;
> rsv->entry[0].size = size;
>
Thanks for the fix. Tested and reviewed.
Reviewed-by: Jonathan Richardson <jonathan.richardson@broadcom.com>
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2019-06-11 1:00 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-06-10 15:05 [PATCH] efi/memreserve: deal with memreserve entries in unmapped memory Ard Biesheuvel
2019-06-10 15:05 ` Ard Biesheuvel
2019-06-10 16:27 ` Ray Jui
2019-06-10 16:27 ` Ray Jui
2019-06-11 1:00 ` Jonathan Richardson
2019-06-11 1:00 ` Jonathan Richardson
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