From: Ard Biesheuvel <ardb@kernel.org> To: Marc Zyngier <maz@kernel.org> Cc: Linux ARM <linux-arm-kernel@lists.infradead.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, wnliu@google.com, Moritz Fischer <mdf@kernel.org>, "# 3.4.x" <stable@vger.kernel.org>, James Morse <james.morse@arm.com>, Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org> Subject: Re: [PATCH v2] firmware/efi: Tell memblock about EFI iomem reservations Date: Fri, 16 Jul 2021 14:10:14 +0200 [thread overview] Message-ID: <CAMj1kXEB6eRPOLAaz7gWgUrpn2R6fy6kJ=S8u_54kNfQCbEfqg@mail.gmail.com> (raw) In-Reply-To: <20210713184326.570923-1-maz@kernel.org> On Tue, 13 Jul 2021 at 20:43, Marc Zyngier <maz@kernel.org> wrote: > > kexec_load_file() relies on the memblock infrastructure to avoid > stamping over regions of memory that are essential to the survival > of the system. > > However, nobody seems to agree how to flag these regions as reserved, > and (for example) EFI only publishes its reservations in /proc/iomem > for the benefit of the traditional, userspace based kexec tool. > > On arm64 platforms with GICv3, this can result in the payload being > placed at the location of the LPI tables. Shock, horror! > > Let's augment the EFI reservation code with a memblock_reserve() call, > protecting our dear tables from the secondary kernel invasion. > > Reported-by: Moritz Fischer <mdf@kernel.org> > Tested-by: Moritz Fischer <mdf@kernel.org> > Signed-off-by: Marc Zyngier <maz@kernel.org> > Cc: stable@vger.kernel.org > Cc: Ard Biesheuvel <ardb@kernel.org> > Cc: James Morse <james.morse@arm.com> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will@kernel.org> Thanks, I'll queue this as a fix. > --- > drivers/firmware/efi/efi.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c > index 4b7ee3fa9224..847f33ffc4ae 100644 > --- a/drivers/firmware/efi/efi.c > +++ b/drivers/firmware/efi/efi.c > @@ -896,6 +896,7 @@ static int __init efi_memreserve_map_root(void) > static int efi_mem_reserve_iomem(phys_addr_t addr, u64 size) > { > struct resource *res, *parent; > + int ret; > > res = kzalloc(sizeof(struct resource), GFP_ATOMIC); > if (!res) > @@ -908,7 +909,17 @@ static int efi_mem_reserve_iomem(phys_addr_t addr, u64 size) > > /* we expect a conflict with a 'System RAM' region */ > parent = request_resource_conflict(&iomem_resource, res); > - return parent ? request_resource(parent, res) : 0; > + ret = parent ? request_resource(parent, res) : 0; > + > + /* > + * Given that efi_mem_reserve_iomem() can be called at any > + * time, only call memblock_reserve() if the architecture > + * keeps the infrastructure around. > + */ > + if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK) && !ret) > + memblock_reserve(addr, size); > + > + return ret; > } > > int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size) > -- > 2.30.2 >
WARNING: multiple messages have this Message-ID (diff)
From: Ard Biesheuvel <ardb@kernel.org> To: Marc Zyngier <maz@kernel.org> Cc: Linux ARM <linux-arm-kernel@lists.infradead.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, wnliu@google.com, Moritz Fischer <mdf@kernel.org>, "# 3.4.x" <stable@vger.kernel.org>, James Morse <james.morse@arm.com>, Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org> Subject: Re: [PATCH v2] firmware/efi: Tell memblock about EFI iomem reservations Date: Fri, 16 Jul 2021 14:10:14 +0200 [thread overview] Message-ID: <CAMj1kXEB6eRPOLAaz7gWgUrpn2R6fy6kJ=S8u_54kNfQCbEfqg@mail.gmail.com> (raw) In-Reply-To: <20210713184326.570923-1-maz@kernel.org> On Tue, 13 Jul 2021 at 20:43, Marc Zyngier <maz@kernel.org> wrote: > > kexec_load_file() relies on the memblock infrastructure to avoid > stamping over regions of memory that are essential to the survival > of the system. > > However, nobody seems to agree how to flag these regions as reserved, > and (for example) EFI only publishes its reservations in /proc/iomem > for the benefit of the traditional, userspace based kexec tool. > > On arm64 platforms with GICv3, this can result in the payload being > placed at the location of the LPI tables. Shock, horror! > > Let's augment the EFI reservation code with a memblock_reserve() call, > protecting our dear tables from the secondary kernel invasion. > > Reported-by: Moritz Fischer <mdf@kernel.org> > Tested-by: Moritz Fischer <mdf@kernel.org> > Signed-off-by: Marc Zyngier <maz@kernel.org> > Cc: stable@vger.kernel.org > Cc: Ard Biesheuvel <ardb@kernel.org> > Cc: James Morse <james.morse@arm.com> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will@kernel.org> Thanks, I'll queue this as a fix. > --- > drivers/firmware/efi/efi.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c > index 4b7ee3fa9224..847f33ffc4ae 100644 > --- a/drivers/firmware/efi/efi.c > +++ b/drivers/firmware/efi/efi.c > @@ -896,6 +896,7 @@ static int __init efi_memreserve_map_root(void) > static int efi_mem_reserve_iomem(phys_addr_t addr, u64 size) > { > struct resource *res, *parent; > + int ret; > > res = kzalloc(sizeof(struct resource), GFP_ATOMIC); > if (!res) > @@ -908,7 +909,17 @@ static int efi_mem_reserve_iomem(phys_addr_t addr, u64 size) > > /* we expect a conflict with a 'System RAM' region */ > parent = request_resource_conflict(&iomem_resource, res); > - return parent ? request_resource(parent, res) : 0; > + ret = parent ? request_resource(parent, res) : 0; > + > + /* > + * Given that efi_mem_reserve_iomem() can be called at any > + * time, only call memblock_reserve() if the architecture > + * keeps the infrastructure around. > + */ > + if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK) && !ret) > + memblock_reserve(addr, size); > + > + return ret; > } > > int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size) > -- > 2.30.2 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-07-16 12:10 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-07-13 18:43 [PATCH v2] firmware/efi: Tell memblock about EFI iomem reservations Marc Zyngier 2021-07-13 18:43 ` Marc Zyngier 2021-07-16 12:10 ` Ard Biesheuvel [this message] 2021-07-16 12:10 ` Ard Biesheuvel
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