| Message ID | 20190610150530.10306-1-ard.biesheuvel@linaro.org |
|---|---|
| State | Accepted |
| Commit | 18df7577adae6c6c778bf774b3aebcacbc1fb439 |
| Headers | show |
| Series | efi/memreserve: deal with memreserve entries in unmapped memory | expand |
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; >
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>
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;
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(-) -- 2.20.1