From 66f93c5a02d5ba6ef17fef459143961382593212 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Thu, 15 Nov 2018 12:34:27 +1000 Subject: powerpc/64: Fix kernel stack 16-byte alignment MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Commit 4c2de74cc869 ("powerpc/64: Interrupts save PPR on stack rather than thread_struct") changed sizeof(struct pt_regs) % 16 from 0 to 8, which causes the interrupt frame allocation on kernel entry to put the kernel stack out of alignment. Quadword (16-byte) alignment for the stack is required by both the 64-bit v1 ABI (v1.9 § 3.2.2) and the 64-bit v2 ABI (v1.1 § 2.2.2.1). Add a pad field to fix alignment, and add a BUILD_BUG_ON to catch this in future. Fixes: 4c2de74cc869 ("powerpc/64: Interrupts save PPR on stack rather than thread_struct") Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/setup_64.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/powerpc/kernel') diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c index 2a51e4cc8246..236c1151a3a7 100644 --- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -636,6 +636,8 @@ static void *__init alloc_stack(unsigned long limit, int cpu) { unsigned long pa; + BUILD_BUG_ON(STACK_INT_FRAME_SIZE % 16); + pa = memblock_alloc_base_nid(THREAD_SIZE, THREAD_SIZE, limit, early_cpu_to_node(cpu), MEMBLOCK_NONE); if (!pa) { -- cgit From fe60522ec60082a1dd735691b82c64f65d4ad15e Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Sun, 18 Nov 2018 17:28:53 -0500 Subject: powerpc/function_graph: Simplify with function_graph_enter() The function_graph_enter() function does the work of calling the function graph hook function and the management of the shadow stack, simplifying the work done in the architecture dependent prepare_ftrace_return(). Have powerpc use the new code, and remove the shadow stack management as well as having to set up the trace structure. This is needed to prepare for a fix of a design bug on how the curr_ret_stack is used. Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Cc: linuxppc-dev@lists.ozlabs.org Cc: stable@kernel.org Fixes: 03274a3ffb449 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback") Reviewed-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- arch/powerpc/kernel/trace/ftrace.c | 15 ++------------- 1 file changed, 2 insertions(+), 13 deletions(-) (limited to 'arch/powerpc/kernel') diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index 4bf051d3e21e..b65c8a34ad6e 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -950,7 +950,6 @@ int ftrace_disable_ftrace_graph_caller(void) */ unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip) { - struct ftrace_graph_ent trace; unsigned long return_hooker; if (unlikely(ftrace_graph_is_dead())) @@ -961,18 +960,8 @@ unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip) return_hooker = ppc_function_entry(return_to_handler); - trace.func = ip; - trace.depth = current->curr_ret_stack + 1; - - /* Only trace if the calling function expects to */ - if (!ftrace_graph_entry(&trace)) - goto out; - - if (ftrace_push_return_trace(parent, ip, &trace.depth, 0, - NULL) == -EBUSY) - goto out; - - parent = return_hooker; + if (!function_graph_enter(parent, ip, 0, NULL)) + parent = return_hooker; out: return parent; } -- cgit