From 5623bc23a1cb9f9a9470fa73b3a20321dc4c4870 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Tue, 25 Feb 2025 10:53:10 +0100 Subject: [PATCH 1/3] s390/traps: Fix test_monitor_call() inline assembly The test_monitor_call() inline assembly uses the xgr instruction, which also modifies the condition code, to clear a register. However the clobber list of the inline assembly does not specify that the condition code is modified, which may lead to incorrect code generation. Use the lhi instruction instead to clear the register without that the condition code is modified. Furthermore this limits clearing to the lower 32 bits of val, since its type is int. Fixes: 17248ea03674 ("s390: fix __EMIT_BUG() macro") Cc: stable@vger.kernel.org Reviewed-by: Juergen Christ Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik --- arch/s390/kernel/traps.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/s390/kernel/traps.c b/arch/s390/kernel/traps.c index 24fee11b030d8..b746213d3110c 100644 --- a/arch/s390/kernel/traps.c +++ b/arch/s390/kernel/traps.c @@ -285,10 +285,10 @@ static void __init test_monitor_call(void) return; asm volatile( " mc 0,0\n" - "0: xgr %0,%0\n" + "0: lhi %[val],0\n" "1:\n" - EX_TABLE(0b,1b) - : "+d" (val)); + EX_TABLE(0b, 1b) + : [val] "+d" (val)); if (!val) panic("Monitor call doesn't work!\n"); } From a22ee38d2efe18edc53791fd1036396c23b43ad0 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= Date: Mon, 17 Feb 2025 14:04:18 +0100 Subject: [PATCH 2/3] selftests/vDSO: Fix GNU hash table entry size for s390x MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Commit 14be4e6f3522 ("selftests: vDSO: fix ELF hash table entry size for s390x") changed the type of the ELF hash table entries to 64bit on s390x. However the *GNU* hash tables entries are always 32bit. The "bucket" pointer is shared between both hash algorithms. On s390, this caused the GNU hash algorithm to access its 32-bit entries as if they were 64-bit, triggering compiler warnings (assignment between "Elf64_Xword *" and "Elf64_Word *") and runtime crashes. Introduce a new dedicated "gnu_bucket" pointer which is used by the GNU hash. Fixes: e0746bde6f82 ("selftests/vDSO: support DT_GNU_HASH") Reviewed-by: Jens Remus Signed-off-by: Thomas Weißschuh Acked-by: Shuah Khan Link: https://lore.kernel.org/r/20250217-selftests-vdso-s390-gnu-hash-v2-1-f6c2532ffe2a@linutronix.de Signed-off-by: Vasily Gorbik --- tools/testing/selftests/vDSO/parse_vdso.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/tools/testing/selftests/vDSO/parse_vdso.c b/tools/testing/selftests/vDSO/parse_vdso.c index 2fe5e983cb22f..f89d052c730eb 100644 --- a/tools/testing/selftests/vDSO/parse_vdso.c +++ b/tools/testing/selftests/vDSO/parse_vdso.c @@ -53,7 +53,7 @@ static struct vdso_info /* Symbol table */ ELF(Sym) *symtab; const char *symstrings; - ELF(Word) *gnu_hash; + ELF(Word) *gnu_hash, *gnu_bucket; ELF_HASH_ENTRY *bucket, *chain; ELF_HASH_ENTRY nbucket, nchain; @@ -185,8 +185,8 @@ void vdso_init_from_sysinfo_ehdr(uintptr_t base) /* The bucket array is located after the header (4 uint32) and the bloom * filter (size_t array of gnu_hash[2] elements). */ - vdso_info.bucket = vdso_info.gnu_hash + 4 + - sizeof(size_t) / 4 * vdso_info.gnu_hash[2]; + vdso_info.gnu_bucket = vdso_info.gnu_hash + 4 + + sizeof(size_t) / 4 * vdso_info.gnu_hash[2]; } else { vdso_info.nbucket = hash[0]; vdso_info.nchain = hash[1]; @@ -268,11 +268,11 @@ void *vdso_sym(const char *version, const char *name) if (vdso_info.gnu_hash) { uint32_t h1 = gnu_hash(name), h2, *hashval; - i = vdso_info.bucket[h1 % vdso_info.nbucket]; + i = vdso_info.gnu_bucket[h1 % vdso_info.nbucket]; if (i == 0) return 0; h1 |= 1; - hashval = vdso_info.bucket + vdso_info.nbucket + + hashval = vdso_info.gnu_bucket + vdso_info.nbucket + (i - vdso_info.gnu_hash[1]); for (;; i++) { ELF(Sym) *sym = &vdso_info.symtab[i]; From b4a1dec11793936ffe1a9fb811724532ff3b1174 Mon Sep 17 00:00:00 2001 From: Sumanth Korikkar Date: Mon, 24 Feb 2025 12:27:04 +0100 Subject: [PATCH 3/3] s390/ftrace: Fix return address recovery of traced function When fgraph is enabled the traced function return address is replaced with trampoline return_to_handler(). The original return address of the traced function is saved in per task return stack along with a stack pointer for reliable stack unwinding via function_graph_enter_regs(). During stack unwinding e.g. for livepatching, ftrace_graph_ret_addr() identifies the original return address of the traced function with the saved stack pointer. With a recent change, the stack pointers passed to ftrace_graph_ret_addr() and function_graph_enter_regs() do not match anymore, and therefore the original return address is not found. Pass the correct stack pointer to function_graph_enter_regs() to fix this. Fixes: 7495e179b478 ("s390/tracing: Enable HAVE_FTRACE_GRAPH_FUNC") Reviewed-by: Heiko Carstens Signed-off-by: Sumanth Korikkar Signed-off-by: Vasily Gorbik --- arch/s390/kernel/ftrace.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c index 63ba6306632ef..e540b022ceb23 100644 --- a/arch/s390/kernel/ftrace.c +++ b/arch/s390/kernel/ftrace.c @@ -266,12 +266,13 @@ void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op, struct ftrace_regs *fregs) { unsigned long *parent = &arch_ftrace_regs(fregs)->regs.gprs[14]; + unsigned long sp = arch_ftrace_regs(fregs)->regs.gprs[15]; if (unlikely(ftrace_graph_is_dead())) return; if (unlikely(atomic_read(¤t->tracing_graph_pause))) return; - if (!function_graph_enter_regs(*parent, ip, 0, parent, fregs)) + if (!function_graph_enter_regs(*parent, ip, 0, (unsigned long *)sp, fregs)) *parent = (unsigned long)&return_to_handler; }