kernel.git/arch/s390/kernel, branch linux-5.18.y

Revert "s390/smp: enforce lowcore protection on CPU restart"

2022-08-17T12:42:35Z

commit 953503751a426413ea8aee2299ae3ee971b70d9b upstream. This reverts commit 6f5c672d17f583b081e283927f5040f726c54598. This breaks normal crash dump when CPU0 is offline. Signed-off-by: Alexander Gordeev Signed-off-by: Greg Kroah-Hartman

kexec, KEYS, s390: Make use of built-in and secondary keyring for signature verification

2022-08-17T12:42:23Z

[ Upstream commit 0828c4a39be57768b8788e8cbd0d84683ea757e5 ] commit e23a8020ce4e ("s390/kexec_file: Signature verification prototype") adds support for KEXEC_SIG verification with keys from platform keyring but the built-in keys and secondary keyring are not used. Add support for the built-in keys and secondary keyring as x86 does. Fixes: e23a8020ce4e ("s390/kexec_file: Signature verification prototype") Cc: stable@vger.kernel.org Cc: Philipp Rudo Cc: kexec@lists.infradead.org Cc: keyrings@vger.kernel.org Cc: linux-security-module@vger.kernel.org Signed-off-by: Michal Suchanek Reviewed-by: "Lee, Chun-Yi" Acked-by: Baoquan He Signed-off-by: Coiby Xu Acked-by: Heiko Carstens Signed-off-by: Mimi Zohar Signed-off-by: Sasha Levin

s390/smp: enforce lowcore protection on CPU restart

2022-08-17T12:42:12Z

[ Upstream commit 6f5c672d17f583b081e283927f5040f726c54598 ] As result of commit 915fea04f932 ("s390/smp: enable DAT before CPU restart callback is called") the low-address protection bit gets mistakenly unset in control register 0 save area of the absolute zero memory. That area is used when manual PSW restart happened to hit an offline CPU. In this case the low-address protection for that CPU will be dropped. Reviewed-by: Heiko Carstens Fixes: 915fea04f932 ("s390/smp: enable DAT before CPU restart callback is called") Signed-off-by: Alexander Gordeev Signed-off-by: Sasha Levin

s390/crash: fix incorrect number of bytes to copy to user space

2022-08-17T12:42:08Z

[ Upstream commit f6749da17a34eb08c9665f072ce7c812ff68aad2 ] The number of bytes in a chunk is correctly calculated, but instead the total number of bytes is passed to copy_to_user_real() function. Reported-by: Matthew Wilcox Fixes: df9694c7975f ("s390/dump: streamline oldmem copy functions") Signed-off-by: Alexander Gordeev Signed-off-by: Sasha Levin

s390/archrandom: simplify back to earlier design and initialize earlier

2022-07-07T15:54:44Z

commit e4f74400308cb8abde5fdc9cad609c2aba32110c upstream. s390x appears to present two RNG interfaces: - a "TRNG" that gathers entropy using some hardware function; and - a "DRBG" that takes in a seed and expands it. Previously, the TRNG was wired up to arch_get_random_{long,int}(), but it was observed that this was being called really frequently, resulting in high overhead. So it was changed to be wired up to arch_get_random_ seed_{long,int}(), which was a reasonable decision. Later on, the DRBG was then wired up to arch_get_random_{long,int}(), with a complicated buffer filling thread, to control overhead and rate. Fortunately, none of the performance issues matter much now. The RNG always attempts to use arch_get_random_seed_{long,int}() first, which means a complicated implementation of arch_get_random_{long,int}() isn't really valuable or useful to have around. And it's only used when reseeding, which means it won't hit the high throughput complications that were faced before. So this commit returns to an earlier design of just calling the TRNG in arch_get_random_seed_{long,int}(), and returning false in arch_get_ random_{long,int}(). Part of what makes the simplification possible is that the RNG now seeds itself using the TRNG at bootup. But this only works if the TRNG is detected early in boot, before random_init() is called. So this commit also causes that check to happen in setup_arch(). Cc: stable@vger.kernel.org Cc: Harald Freudenberger Cc: Ingo Franzki Cc: Juergen Christ Cc: Heiko Carstens Signed-off-by: Jason A. Donenfeld Link: https://lore.kernel.org/r/20220610222023.378448-1-Jason@zx2c4.com Reviewed-by: Harald Freudenberger Acked-by: Heiko Carstens Signed-off-by: Alexander Gordeev Signed-off-by: Greg Kroah-Hartman

s390/crash: make copy_oldmem_page() return number of bytes copied

2022-06-29T07:04:36Z

[ Upstream commit af2debd58bd769e38f538143f0d332e15d753396 ] Callback copy_oldmem_page() returns either error code or zero. Instead, it should return the error code or number of bytes copied. Fixes: df9694c7975f ("s390/dump: streamline oldmem copy functions") Reviewed-by: Alexander Egorenkov Tested-by: Alexander Egorenkov Signed-off-by: Alexander Gordeev Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

s390/crash: add missing iterator advance in copy_oldmem_page()

2022-06-29T07:04:36Z

[ Upstream commit cc02e6e21aa5f2ac0defe8c15e5a9d024da6e73d ] In case old memory was successfully copied the passed iterator should be advanced as well. Currently copy_oldmem_page() is always called with single-segment iterator. Should that ever change - copy_oldmem_user and copy_oldmem_kernel() functions would need a rework to deal with multi-segment iterators. Fixes: 5d8de293c224 ("vmcore: convert copy_oldmem_page() to take an iov_iter") Reviewed-by: Alexander Egorenkov Tested-by: Alexander Egorenkov Signed-off-by: Alexander Gordeev Signed-off-by: Sasha Levin

vmcore: convert copy_oldmem_page() to take an iov_iter

2022-06-29T07:04:36Z

[ Upstream commit 5d8de293c224896a4da99763fce4f9794308caf4 ] Patch series "Convert vmcore to use an iov_iter", v5. For some reason several people have been sending bad patches to fix compiler warnings in vmcore recently. Here's how it should be done. Compile-tested only on x86. As noted in the first patch, s390 should take this conversion a bit further, but I'm not inclined to do that work myself. This patch (of 3): Instead of passing in a 'buf' and 'userbuf' argument, pass in an iov_iter. s390 needs more work to pass the iov_iter down further, or refactor, but I'd be more comfortable if someone who can test on s390 did that work. It's more convenient to convert the whole of read_from_oldmem() to take an iov_iter at the same time, so rename it to read_from_oldmem_iter() and add a temporary read_from_oldmem() wrapper that creates an iov_iter. Link: https://lkml.kernel.org/r/20220408090636.560886-1-bhe@redhat.com Link: https://lkml.kernel.org/r/20220408090636.560886-2-bhe@redhat.com Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Baoquan He Reviewed-by: Christoph Hellwig Cc: Heiko Carstens Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin

s390/cpumf: Handle events cycles and instructions identical

2022-06-29T07:04:35Z

[ Upstream commit be857b7f77d130dbbd47c91fc35198b040f35865 ] Events CPU_CYCLES and INSTRUCTIONS can be submitted with two different perf_event attribute::type values: - PERF_TYPE_HARDWARE: when invoked via perf tool predefined events name cycles or cpu-cycles or instructions. - pmu->type: when invoked via perf tool event name cpu_cf/CPU_CYLCES/ or cpu_cf/INSTRUCTIONS/. This invocation also selects the PMU to which the event belongs. Handle both type of invocations identical for events CPU_CYLCES and INSTRUCTIONS. They address the same hardware. The result is different when event modifier exclude_kernel is also set. Invocation with event modifier for user space event counting fails. Output before: # perf stat -e cpum_cf/cpu_cycles/u -- true Performance counter stats for 'true': cpum_cf/cpu_cycles/u 0.000761033 seconds time elapsed 0.000076000 seconds user 0.000725000 seconds sys # Output after: # perf stat -e cpum_cf/cpu_cycles/u -- true Performance counter stats for 'true': 349,613 cpum_cf/cpu_cycles/u 0.000844143 seconds time elapsed 0.000079000 seconds user 0.000800000 seconds sys # Fixes: 6a82e23f45fe ("s390/cpumf: Adjust registration of s390 PMU device drivers") Signed-off-by: Thomas Richter Acked-by: Sumanth Korikkar [agordeev@linux.ibm.com corrected commit ID of Fixes commit] Signed-off-by: Alexander Gordeev Signed-off-by: Sasha Levin

s390/mcck: isolate SIE instruction when setting CIF_MCCK_GUEST flag

2022-06-14T16:44:59Z

[ Upstream commit 29ccaa4b35ea874ddd50518e5c2c746b9238a792 ] Commit d768bd892fc8 ("s390: add options to change branch prediction behaviour for the kernel") introduced .Lsie_exit label - supposedly to fence off SIE instruction. However, the corresponding address range length .Lsie_crit_mcck_length was not updated, which led to BPON code potentionally marked with CIF_MCCK_GUEST flag. Both .Lsie_exit and .Lsie_crit_mcck_length were removed with commit 0b0ed657fe00 ("s390: remove critical section cleanup from entry.S"), but the issue persisted - currently BPOFF and BPENTER macros might get wrongly considered by the machine check handler as a guest. Fixes: d768bd892fc8 ("s390: add options to change branch prediction behaviour for the kernel") Reviewed-by: Sven Schnelle Reviewed-by: Christian Borntraeger Signed-off-by: Alexander Gordeev Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin