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Sat, 09 Nov 2019 23:33:58 -0800 (PST) MIME-Version: 1.0 References: <20191110024013.29782-1-sashal@kernel.org> <20191110024013.29782-133-sashal@kernel.org> In-Reply-To: <20191110024013.29782-133-sashal@kernel.org> From: Ard Biesheuvel Date: Sun, 10 Nov 2019 08:33:47 +0100 Message-ID: Subject: Re: [PATCH AUTOSEL 4.19 133/191] efi: honour memory reservations passed via a linux specific config table To: Sasha Levin Cc: Linux Kernel Mailing List , stable , Jeremy Linton , linux-efi Content-Type: text/plain; charset="UTF-8" Sender: linux-efi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org On Sun, 10 Nov 2019 at 03:44, Sasha Levin wrote: > > From: Ard Biesheuvel > > [ Upstream commit 71e0940d52e107748b270213a01d3b1546657d74 ] > > In order to allow the OS to reserve memory persistently across a > kexec, introduce a Linux-specific UEFI configuration table that > points to the head of a linked list in memory, allowing each kernel > to add list items describing memory regions that the next kernel > should treat as reserved. > > This is useful, e.g., for GICv3 based ARM systems that cannot disable > DMA access to the LPI tables, forcing them to reuse the same memory > region again after a kexec reboot. > > Tested-by: Jeremy Linton > Signed-off-by: Ard Biesheuvel > Signed-off-by: Sasha Levin NAK This doesn't belong in -stable, and I'd be interested in understanding how this got autoselected, and how I can prevent this from happening again in the future. > --- > drivers/firmware/efi/efi.c | 27 ++++++++++++++++++++++++++- > include/linux/efi.h | 8 ++++++++ > 2 files changed, 34 insertions(+), 1 deletion(-) > > diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c > index d54fca902e64f..f265309859781 100644 > --- a/drivers/firmware/efi/efi.c > +++ b/drivers/firmware/efi/efi.c > @@ -52,7 +52,8 @@ struct efi __read_mostly efi = { > .properties_table = EFI_INVALID_TABLE_ADDR, > .mem_attr_table = EFI_INVALID_TABLE_ADDR, > .rng_seed = EFI_INVALID_TABLE_ADDR, > - .tpm_log = EFI_INVALID_TABLE_ADDR > + .tpm_log = EFI_INVALID_TABLE_ADDR, > + .mem_reserve = EFI_INVALID_TABLE_ADDR, > }; > EXPORT_SYMBOL(efi); > > @@ -487,6 +488,7 @@ static __initdata efi_config_table_type_t common_tables[] = { > {EFI_MEMORY_ATTRIBUTES_TABLE_GUID, "MEMATTR", &efi.mem_attr_table}, > {LINUX_EFI_RANDOM_SEED_TABLE_GUID, "RNG", &efi.rng_seed}, > {LINUX_EFI_TPM_EVENT_LOG_GUID, "TPMEventLog", &efi.tpm_log}, > + {LINUX_EFI_MEMRESERVE_TABLE_GUID, "MEMRESERVE", &efi.mem_reserve}, > {NULL_GUID, NULL, NULL}, > }; > > @@ -594,6 +596,29 @@ int __init efi_config_parse_tables(void *config_tables, int count, int sz, > early_memunmap(tbl, sizeof(*tbl)); > } > > + if (efi.mem_reserve != EFI_INVALID_TABLE_ADDR) { > + unsigned long prsv = efi.mem_reserve; > + > + while (prsv) { > + struct linux_efi_memreserve *rsv; > + > + /* reserve the entry itself */ > + memblock_reserve(prsv, sizeof(*rsv)); > + > + rsv = early_memremap(prsv, sizeof(*rsv)); > + if (rsv == NULL) { > + pr_err("Could not map UEFI memreserve entry!\n"); > + return -ENOMEM; > + } > + > + if (rsv->size) > + memblock_reserve(rsv->base, rsv->size); > + > + prsv = rsv->next; > + early_memunmap(rsv, sizeof(*rsv)); > + } > + } > + > return 0; > } > > diff --git a/include/linux/efi.h b/include/linux/efi.h > index cc3391796c0b8..f43fc61fbe2c9 100644 > --- a/include/linux/efi.h > +++ b/include/linux/efi.h > @@ -672,6 +672,7 @@ void efi_native_runtime_setup(void); > #define LINUX_EFI_LOADER_ENTRY_GUID EFI_GUID(0x4a67b082, 0x0a4c, 0x41cf, 0xb6, 0xc7, 0x44, 0x0b, 0x29, 0xbb, 0x8c, 0x4f) > #define LINUX_EFI_RANDOM_SEED_TABLE_GUID EFI_GUID(0x1ce1e5bc, 0x7ceb, 0x42f2, 0x81, 0xe5, 0x8a, 0xad, 0xf1, 0x80, 0xf5, 0x7b) > #define LINUX_EFI_TPM_EVENT_LOG_GUID EFI_GUID(0xb7799cb0, 0xeca2, 0x4943, 0x96, 0x67, 0x1f, 0xae, 0x07, 0xb7, 0x47, 0xfa) > +#define LINUX_EFI_MEMRESERVE_TABLE_GUID EFI_GUID(0x888eb0c6, 0x8ede, 0x4ff5, 0xa8, 0xf0, 0x9a, 0xee, 0x5c, 0xb9, 0x77, 0xc2) > > typedef struct { > efi_guid_t guid; > @@ -957,6 +958,7 @@ extern struct efi { > unsigned long mem_attr_table; /* memory attributes table */ > unsigned long rng_seed; /* UEFI firmware random seed */ > unsigned long tpm_log; /* TPM2 Event Log table */ > + unsigned long mem_reserve; /* Linux EFI memreserve table */ > efi_get_time_t *get_time; > efi_set_time_t *set_time; > efi_get_wakeup_time_t *get_wakeup_time; > @@ -1667,4 +1669,10 @@ extern int efi_tpm_eventlog_init(void); > /* Workqueue to queue EFI Runtime Services */ > extern struct workqueue_struct *efi_rts_wq; > > +struct linux_efi_memreserve { > + phys_addr_t next; > + phys_addr_t base; > + phys_addr_t size; > +}; > + > #endif /* _LINUX_EFI_H */ > -- > 2.20.1 >