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

s390/unwind: fix fgraph return address recovery

2022-08-17T12:42:28+00:00

[ Upstream commit ded466e1806686794b403ebf031133bbaca76bb2 ] When HAVE_FUNCTION_GRAPH_RET_ADDR_PTR is defined, the return address to the fgraph caller is recovered by tagging it along with the stack pointer of ftrace stack. This makes the stack unwinding more reliable. When the fgraph return address is modified to return_to_handler, ftrace_graph_ret_addr tries to restore it to the original value using tagged stack pointer. Fix this by passing tagged sp to ftrace_graph_ret_addr. Fixes: d81675b60d09 ("s390/unwind: recover kretprobe modified return address in stacktrace") Cc: # 5.18 Reviewed-by: Vasily Gorbik Signed-off-by: Sumanth Korikkar Signed-off-by: Alexander Gordeev Signed-off-by: Sasha Levin

kexec_file: drop weak attribute from functions

2022-08-17T12:42:23+00:00

[ Upstream commit 65d9a9a60fd71be964effb2e94747a6acb6e7015 ] As requested (http://lkml.kernel.org/r/87ee0q7b92.fsf@email.froward.int.ebiederm.org), this series converts weak functions in kexec to use the #ifdef approach. Quoting the 3e35142ef99fe ("kexec_file: drop weak attribute from arch_kexec_apply_relocations[_add]") changelog: : Since commit d1bcae833b32f1 ("ELF: Don't generate unused section symbols") : [1], binutils (v2.36+) started dropping section symbols that it thought : were unused. This isn't an issue in general, but with kexec_file.c, gcc : is placing kexec_arch_apply_relocations[_add] into a separate : .text.unlikely section and the section symbol ".text.unlikely" is being : dropped. Due to this, recordmcount is unable to find a non-weak symbol in : .text.unlikely to generate a relocation record against. This patch (of 2); Drop __weak attribute from functions in kexec_file.c: - arch_kexec_kernel_image_probe() - arch_kimage_file_post_load_cleanup() - arch_kexec_kernel_image_load() - arch_kexec_locate_mem_hole() - arch_kexec_kernel_verify_sig() arch_kexec_kernel_image_load() calls into kexec_image_load_default(), so drop the static attribute for the latter. arch_kexec_kernel_verify_sig() is not overridden by any architecture, so drop the __weak attribute. Link: https://lkml.kernel.org/r/cover.1656659357.git.naveen.n.rao@linux.vnet.ibm.com Link: https://lkml.kernel.org/r/2cd7ca1fe4d6bb6ca38e3283c717878388ed6788.1656659357.git.naveen.n.rao@linux.vnet.ibm.com Signed-off-by: Naveen N. Rao Suggested-by: Eric Biederman Signed-off-by: Andrew Morton Signed-off-by: Mimi Zohar Signed-off-by: Sasha Levin

KVM: s390: pv: leak the topmost page table when destroy fails

2022-08-17T12:41:47+00:00

[ Upstream commit faa2f72cb3569256480c5540d242c84e99965160 ] Each secure guest must have a unique ASCE (address space control element); we must avoid that new guests use the same page for their ASCE, to avoid errors. Since the ASCE mostly consists of the address of the topmost page table (plus some flags), we must not return that memory to the pool unless the ASCE is no longer in use. Only a successful Destroy Secure Configuration UVC will make the ASCE reusable again. If the Destroy Configuration UVC fails, the ASCE cannot be reused for a secure guest (either for the ASCE or for other memory areas). To avoid a collision, it must not be used again. This is a permanent error and the page becomes in practice unusable, so we set it aside and leak it. On failure we already leak other memory that belongs to the ultravisor (i.e. the variable and base storage for a guest) and not leaking the topmost page table was an oversight. This error (and thus the leakage) should not happen unless the hardware is broken or KVM has some unknown serious bug. Signed-off-by: Claudio Imbrenda Fixes: 29b40f105ec8d55 ("KVM: s390: protvirt: Add initial vm and cpu lifecycle handling") Reviewed-by: Janosch Frank Link: https://lore.kernel.org/r/20220628135619.32410-2-imbrenda@linux.ibm.com Message-Id: <20220628135619.32410-2-imbrenda@linux.ibm.com> Signed-off-by: Janosch Frank Signed-off-by: Sasha Levin

s390/archrandom: prevent CPACF trng invocations in interrupt context

2022-08-03T10:05:18+00:00

commit 918e75f77af7d2e049bb70469ec0a2c12782d96a upstream. This patch slightly reworks the s390 arch_get_random_seed_{int,long} implementation: Make sure the CPACF trng instruction is never called in any interrupt context. This is done by adding an additional condition in_task(). Justification: There are some constrains to satisfy for the invocation of the arch_get_random_seed_{int,long}() functions: - They should provide good random data during kernel initialization. - They should not be called in interrupt context as the TRNG instruction is relatively heavy weight and may for example make some network loads cause to timeout and buck. However, it was not clear what kind of interrupt context is exactly encountered during kernel init or network traffic eventually calling arch_get_random_seed_long(). After some days of investigations it is clear that the s390 start_kernel function is not running in any interrupt context and so the trng is called: Jul 11 18:33:39 t35lp54 kernel: [<00000001064e90ca>] arch_get_random_seed_long.part.0+0x32/0x70 Jul 11 18:33:39 t35lp54 kernel: [<000000010715f246>] random_init+0xf6/0x238 Jul 11 18:33:39 t35lp54 kernel: [<000000010712545c>] start_kernel+0x4a4/0x628 Jul 11 18:33:39 t35lp54 kernel: [<000000010590402a>] startup_continue+0x2a/0x40 The condition in_task() is true and the CPACF trng provides random data during kernel startup. The network traffic however, is more difficult. A typical call stack looks like this: Jul 06 17:37:07 t35lp54 kernel: [<000000008b5600fc>] extract_entropy.constprop.0+0x23c/0x240 Jul 06 17:37:07 t35lp54 kernel: [<000000008b560136>] crng_reseed+0x36/0xd8 Jul 06 17:37:07 t35lp54 kernel: [<000000008b5604b8>] crng_make_state+0x78/0x340 Jul 06 17:37:07 t35lp54 kernel: [<000000008b5607e0>] _get_random_bytes+0x60/0xf8 Jul 06 17:37:07 t35lp54 kernel: [<000000008b56108a>] get_random_u32+0xda/0x248 Jul 06 17:37:07 t35lp54 kernel: [<000000008aefe7a8>] kfence_guarded_alloc+0x48/0x4b8 Jul 06 17:37:07 t35lp54 kernel: [<000000008aeff35e>] __kfence_alloc+0x18e/0x1b8 Jul 06 17:37:07 t35lp54 kernel: [<000000008aef7f10>] __kmalloc_node_track_caller+0x368/0x4d8 Jul 06 17:37:07 t35lp54 kernel: [<000000008b611eac>] kmalloc_reserve+0x44/0xa0 Jul 06 17:37:07 t35lp54 kernel: [<000000008b611f98>] __alloc_skb+0x90/0x178 Jul 06 17:37:07 t35lp54 kernel: [<000000008b6120dc>] __napi_alloc_skb+0x5c/0x118 Jul 06 17:37:07 t35lp54 kernel: [<000000008b8f06b4>] qeth_extract_skb+0x13c/0x680 Jul 06 17:37:07 t35lp54 kernel: [<000000008b8f6526>] qeth_poll+0x256/0x3f8 Jul 06 17:37:07 t35lp54 kernel: [<000000008b63d76e>] __napi_poll.constprop.0+0x46/0x2f8 Jul 06 17:37:07 t35lp54 kernel: [<000000008b63dbec>] net_rx_action+0x1cc/0x408 Jul 06 17:37:07 t35lp54 kernel: [<000000008b937302>] __do_softirq+0x132/0x6b0 Jul 06 17:37:07 t35lp54 kernel: [<000000008abf46ce>] __irq_exit_rcu+0x13e/0x170 Jul 06 17:37:07 t35lp54 kernel: [<000000008abf531a>] irq_exit_rcu+0x22/0x50 Jul 06 17:37:07 t35lp54 kernel: [<000000008b922506>] do_io_irq+0xe6/0x198 Jul 06 17:37:07 t35lp54 kernel: [<000000008b935826>] io_int_handler+0xd6/0x110 Jul 06 17:37:07 t35lp54 kernel: [<000000008b9358a6>] psw_idle_exit+0x0/0xa Jul 06 17:37:07 t35lp54 kernel: ([<000000008ab9c59a>] arch_cpu_idle+0x52/0xe0) Jul 06 17:37:07 t35lp54 kernel: [<000000008b933cfe>] default_idle_call+0x6e/0xd0 Jul 06 17:37:07 t35lp54 kernel: [<000000008ac59f4e>] do_idle+0xf6/0x1b0 Jul 06 17:37:07 t35lp54 kernel: [<000000008ac5a28e>] cpu_startup_entry+0x36/0x40 Jul 06 17:37:07 t35lp54 kernel: [<000000008abb0d90>] smp_start_secondary+0x148/0x158 Jul 06 17:37:07 t35lp54 kernel: [<000000008b935b9e>] restart_int_handler+0x6e/0x90 which confirms that the call is in softirq context. So in_task() covers exactly the cases where we want to have CPACF trng called: not in nmi, not in hard irq, not in soft irq but in normal task context and during kernel init. Signed-off-by: Harald Freudenberger Acked-by: Jason A. Donenfeld Reviewed-by: Juergen Christ Link: https://lore.kernel.org/r/20220713131721.257907-1-freude@linux.ibm.com Fixes: e4f74400308c ("s390/archrandom: simplify back to earlier design and initialize earlier") [agordeev@linux.ibm.com changed desc, added Fixes and Link, removed -stable] Signed-off-by: Alexander Gordeev Signed-off-by: Greg Kroah-Hartman

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

2022-07-07T15:54:44+00:00

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

kexec_file: drop weak attribute from arch_kexec_apply_relocations[_add]

2022-06-09T08:30:51+00:00

commit 3e35142ef99fe6b4fe5d834ad43ee13cca10a2dc upstream. Since commit d1bcae833b32f1 ("ELF: Don't generate unused section symbols") [1], binutils (v2.36+) started dropping section symbols that it thought were unused. This isn't an issue in general, but with kexec_file.c, gcc is placing kexec_arch_apply_relocations[_add] into a separate .text.unlikely section and the section symbol ".text.unlikely" is being dropped. Due to this, recordmcount is unable to find a non-weak symbol in .text.unlikely to generate a relocation record against. Address this by dropping the weak attribute from these functions. Instead, follow the existing pattern of having architectures #define the name of the function they want to override in their headers. [1] https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=d1bcae833b32f1 [akpm@linux-foundation.org: arch/s390/include/asm/kexec.h needs linux/module.h] Link: https://lkml.kernel.org/r/20220519091237.676736-1-naveen.n.rao@linux.vnet.ibm.com Signed-off-by: Michael Ellerman Signed-off-by: Naveen N. Rao Cc: "Eric W. Biederman" Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

s390/stp: clock_delta should be signed

2022-06-09T08:30:45+00:00

commit 5ace65ebb5ce9fe1cc8fdbdd97079fb566ef0ea4 upstream. clock_delta is declared as unsigned long in various places. However, the clock sync delta can be negative. This would add a huge positive offset in clock_sync_global where clock_delta is added to clk.eitod which is a 72 bit integer. Declare it as signed long to fix this. Cc: stable@vger.kernel.org Signed-off-by: Sven Schnelle Reviewed-by: Heiko Carstens Signed-off-by: Heiko Carstens Signed-off-by: Greg Kroah-Hartman

s390/preempt: disable __preempt_count_add() optimization for PROFILE_ALL_BRANCHES

2022-06-09T08:29:41+00:00

[ Upstream commit 63678eecec57fc51b778be3da35a397931287170 ] gcc 12 does not (always) optimize away code that should only be generated if parameters are constant and within in a certain range. This depends on various obscure kernel config options, however in particular PROFILE_ALL_BRANCHES can trigger this compile error: In function ‘__atomic_add_const’, inlined from ‘__preempt_count_add.part.0’ at ./arch/s390/include/asm/preempt.h:50:3: ./arch/s390/include/asm/atomic_ops.h:80:9: error: impossible constraint in ‘asm’ 80 | asm volatile( \ | ^~~ Workaround this by simply disabling the optimization for PROFILE_ALL_BRANCHES, since the kernel will be so slow, that this optimization won't matter at all. Reported-by: Thomas Richter Reviewed-by: Sven Schnelle Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin

s390: define get_cycles macro for arch-override

2022-05-30T07:24:04+00:00

commit 2e3df523256cb9836de8441e9c791a796759bb3c upstream. S390x defines a get_cycles() function, but it does not do the usual `#define get_cycles get_cycles` dance, making it impossible for generic code to see if an arch-specific function was defined. While the get_cycles() ifdef is not currently used, the following timekeeping patch in this series will depend on the macro existing (or not existing) when defining random_get_entropy(). Cc: Thomas Gleixner Cc: Arnd Bergmann Cc: Vasily Gorbik Cc: Alexander Gordeev Cc: Christian Borntraeger Cc: Sven Schnelle Acked-by: Heiko Carstens Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman

s390: current_stack_pointer shouldn't be a function

2022-04-12T09:56:08+00:00

s390 defines current_stack_pointer as function while all other architectures use 'register unsigned long asm(""). This make codes like the following from check_stack_object() fail: if (IS_ENABLED(CONFIG_STACK_GROWSUP)) { if ((void *)current_stack_pointer < obj + len) return BAD_STACK; } else { if (obj < (void *)current_stack_pointer) return BAD_STACK; } because this would compare the address of current_stack_pointer() and not the stackpointer value. Reported-by: Karsten Graul Fixes: 2792d84e6da5 ("usercopy: Check valid lifetime via stack depth") Cc: Kees Cook Cc: Vasily Gorbik Cc: Alexander Gordeev Signed-off-by: Sven Schnelle Reviewed-by: Heiko Carstens Signed-off-by: Heiko Carstens