| Message ID | 20230615123703.4028156-2-mpe@ellerman.id.au (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2,1/2] powerpc/tpm: Create linux,sml-base/size as big endian | expand |
On 6/15/23 08:37, Michael Ellerman wrote: > The TPM code in prom_init.c creates a small buffer of memory to store > the TPM's SML (Stored Measurement Log). It's communicated to Linux via > the linux,sml-base/size device tree properties of the TPM node. > > When kexec'ing that buffer can be overwritten, or when kdump'ing it may > not be mapped by the second kernel. The latter can lead to a crash when > booting the second kernel such as: > > tpm_ibmvtpm 71000003: CRQ initialization completed > BUG: Unable to handle kernel data access on read at 0xc00000002ffb0000 > Faulting instruction address: 0xc0000000200a70e0 > Oops: Kernel access of bad area, sig: 11 [#1] > LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries > Modules linked in: > CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.2.0-rc2-00134-g9307ce092f5d #314 > Hardware name: IBM pSeries (emulated by qemu) POWER9 (raw) 0x4e1200 0xf000005 of:SLOF,git-5b4c5a pSeries > NIP: c0000000200a70e0 LR: c0000000203dd5dc CTR: 0000000000000800 > REGS: c000000024543280 TRAP: 0300 Not tainted (6.2.0-rc2-00134-g9307ce092f5d) > MSR: 8000000002009033 <SF,VEC,EE,ME,IR,DR,RI,LE> CR: 24002280 XER: 00000006 > CFAR: c0000000200a70c8 DAR: c00000002ffb0000 DSISR: 40000000 IRQMASK: 0 > ... > NIP memcpy_power7+0x400/0x7d0 > LR kmemdup+0x5c/0x80 > Call Trace: > memcpy_power7+0x274/0x7d0 (unreliable) > kmemdup+0x5c/0x80 > tpm_read_log_of+0xe8/0x1b0 > tpm_bios_log_setup+0x60/0x210 > tpm_chip_register+0x134/0x320 > tpm_ibmvtpm_probe+0x520/0x7d0 > vio_bus_probe+0x9c/0x460 > really_probe+0x104/0x420 > __driver_probe_device+0xb0/0x170 > driver_probe_device+0x58/0x180 > __driver_attach+0xd8/0x250 > bus_for_each_dev+0xb4/0x140 > driver_attach+0x34/0x50 > bus_add_driver+0x1e8/0x2d0 > driver_register+0xb4/0x1c0 > __vio_register_driver+0x74/0x9c > ibmvtpm_module_init+0x34/0x48 > do_one_initcall+0x80/0x320 > kernel_init_freeable+0x304/0x3ac > kernel_init+0x30/0x1a0 > ret_from_kernel_thread+0x5c/0x64 > > To fix the crash, add the SML region to the usable memory areas for the > kdump kernel, so that the second kernel will map the region. To avoid > corruption of the region, add the region to the reserved memory areas, To me the 2nd paragraph and the one below seem to say that in general it does NOT 'avoid corruption of the region.' > so that the second kernel does not use the memory for something else. > > Note that when loading a kdump kernel with the regular kexec_load() > syscall the SML may be overwritten by the kdump kernel, depending on > where the SML is in memory in relation to the crashkernel region. That > is a separate problem that is not solved by this patch. > > Fixes: a0458284f062 ("powerpc: Add support code for kexec_file_load()") > Reported-by: Stefan Berger <stefanb@linux.ibm.com> > Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> I agree to the code: Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
diff --git a/arch/powerpc/include/asm/kexec_ranges.h b/arch/powerpc/include/asm/kexec_ranges.h index f83866a19e87..cf6a97f9113d 100644 --- a/arch/powerpc/include/asm/kexec_ranges.h +++ b/arch/powerpc/include/asm/kexec_ranges.h @@ -21,5 +21,6 @@ int add_kernel_mem_range(struct crash_mem **mem_ranges); int add_rtas_mem_range(struct crash_mem **mem_ranges); int add_opal_mem_range(struct crash_mem **mem_ranges); int add_reserved_mem_ranges(struct crash_mem **mem_ranges); +int add_sml_mem_range(struct crash_mem **mem_ranges); #endif /* _ASM_POWERPC_KEXEC_RANGES_H */ diff --git a/arch/powerpc/kexec/file_load_64.c b/arch/powerpc/kexec/file_load_64.c index 110d28bede2a..90c10a89fcbc 100644 --- a/arch/powerpc/kexec/file_load_64.c +++ b/arch/powerpc/kexec/file_load_64.c @@ -79,6 +79,10 @@ static int get_exclude_memory_ranges(struct crash_mem **mem_ranges) if (ret) goto out; + ret = add_sml_mem_range(mem_ranges); + if (ret) + goto out; + ret = add_opal_mem_range(mem_ranges); if (ret) goto out; @@ -122,6 +126,10 @@ static int get_usable_memory_ranges(struct crash_mem **mem_ranges) if (ret) goto out; + ret = add_sml_mem_range(mem_ranges); + if (ret) + goto out; + ret = add_opal_mem_range(mem_ranges); if (ret) goto out; @@ -225,6 +233,10 @@ static int get_reserved_memory_ranges(struct crash_mem **mem_ranges) if (ret) goto out; + ret = add_sml_mem_range(mem_ranges); + if (ret) + goto out; + ret = add_tce_mem_ranges(mem_ranges); if (ret) goto out; diff --git a/arch/powerpc/kexec/ranges.c b/arch/powerpc/kexec/ranges.c index 5fc53a5fcfdf..8b01655ceb5e 100644 --- a/arch/powerpc/kexec/ranges.c +++ b/arch/powerpc/kexec/ranges.c @@ -350,6 +350,26 @@ int add_rtas_mem_range(struct crash_mem **mem_ranges) return ret; } +int add_sml_mem_range(struct crash_mem **mem_ranges) +{ + struct device_node *dn; + int ret = 0; + u64 base; + u32 size; + + // Matches the device type in tpm_ibmvtpm.c + for_each_node_by_type(dn, "IBM,vtpm") { + if (of_property_read_u64(dn, "linux,sml-base", &base) == 0 && + of_property_read_u32(dn, "linux,sml-size", &size) == 0) { + ret = add_mem_range(mem_ranges, base, size); + if (ret) + break; + } + } + + return ret; +} + /** * add_opal_mem_range - Adds OPAL region to the given memory ranges list. * @mem_ranges: Range list to add the memory range to.
The TPM code in prom_init.c creates a small buffer of memory to store the TPM's SML (Stored Measurement Log). It's communicated to Linux via the linux,sml-base/size device tree properties of the TPM node. When kexec'ing that buffer can be overwritten, or when kdump'ing it may not be mapped by the second kernel. The latter can lead to a crash when booting the second kernel such as: tpm_ibmvtpm 71000003: CRQ initialization completed BUG: Unable to handle kernel data access on read at 0xc00000002ffb0000 Faulting instruction address: 0xc0000000200a70e0 Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.2.0-rc2-00134-g9307ce092f5d #314 Hardware name: IBM pSeries (emulated by qemu) POWER9 (raw) 0x4e1200 0xf000005 of:SLOF,git-5b4c5a pSeries NIP: c0000000200a70e0 LR: c0000000203dd5dc CTR: 0000000000000800 REGS: c000000024543280 TRAP: 0300 Not tainted (6.2.0-rc2-00134-g9307ce092f5d) MSR: 8000000002009033 <SF,VEC,EE,ME,IR,DR,RI,LE> CR: 24002280 XER: 00000006 CFAR: c0000000200a70c8 DAR: c00000002ffb0000 DSISR: 40000000 IRQMASK: 0 ... NIP memcpy_power7+0x400/0x7d0 LR kmemdup+0x5c/0x80 Call Trace: memcpy_power7+0x274/0x7d0 (unreliable) kmemdup+0x5c/0x80 tpm_read_log_of+0xe8/0x1b0 tpm_bios_log_setup+0x60/0x210 tpm_chip_register+0x134/0x320 tpm_ibmvtpm_probe+0x520/0x7d0 vio_bus_probe+0x9c/0x460 really_probe+0x104/0x420 __driver_probe_device+0xb0/0x170 driver_probe_device+0x58/0x180 __driver_attach+0xd8/0x250 bus_for_each_dev+0xb4/0x140 driver_attach+0x34/0x50 bus_add_driver+0x1e8/0x2d0 driver_register+0xb4/0x1c0 __vio_register_driver+0x74/0x9c ibmvtpm_module_init+0x34/0x48 do_one_initcall+0x80/0x320 kernel_init_freeable+0x304/0x3ac kernel_init+0x30/0x1a0 ret_from_kernel_thread+0x5c/0x64 To fix the crash, add the SML region to the usable memory areas for the kdump kernel, so that the second kernel will map the region. To avoid corruption of the region, add the region to the reserved memory areas, so that the second kernel does not use the memory for something else. Note that when loading a kdump kernel with the regular kexec_load() syscall the SML may be overwritten by the kdump kernel, depending on where the SML is in memory in relation to the crashkernel region. That is a separate problem that is not solved by this patch. Fixes: a0458284f062 ("powerpc: Add support code for kexec_file_load()") Reported-by: Stefan Berger <stefanb@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> --- arch/powerpc/include/asm/kexec_ranges.h | 1 + arch/powerpc/kexec/file_load_64.c | 12 ++++++++++++ arch/powerpc/kexec/ranges.c | 20 ++++++++++++++++++++ 3 files changed, 33 insertions(+) v2: Add fixes tag as suggested by Jarkko. Make change log clearer that this only fixes kexec_file_load().