diff options
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 2 | ||||
| -rw-r--r-- | Documentation/trace/debugging.rst | 2 | ||||
| -rw-r--r-- | kernel/trace/ring_buffer.c | 5 | ||||
| -rw-r--r-- | kernel/trace/trace.c | 66 | ||||
| -rw-r--r-- | kernel/trace/trace.h | 1 |
5 files changed, 50 insertions, 26 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 3f35d5b8c296..f5af86b3c4a2 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -7288,6 +7288,8 @@ This is just one of many ways that can clear memory. Make sure your system keeps the content of memory across reboots before relying on this option. + NB: Both the mapped address and size must be page aligned for the architecture. + See also Documentation/trace/debugging.rst diff --git a/Documentation/trace/debugging.rst b/Documentation/trace/debugging.rst index 54fb16239d70..d54bc500af80 100644 --- a/Documentation/trace/debugging.rst +++ b/Documentation/trace/debugging.rst @@ -136,6 +136,8 @@ kernel, so only the same kernel is guaranteed to work if the mapping is preserved. Switching to a different kernel version may find a different layout and mark the buffer as invalid. +NB: Both the mapped address and size must be page aligned for the architecture. + Using trace_printk() in the boot instance ----------------------------------------- By default, the content of trace_printk() goes into the top level tracing diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index d8d7b28e2c2f..c0f877d39a24 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -6016,7 +6016,7 @@ static void rb_update_meta_page(struct ring_buffer_per_cpu *cpu_buffer) meta->read = cpu_buffer->read; /* Some archs do not have data cache coherency between kernel and user-space */ - flush_dcache_folio(virt_to_folio(cpu_buffer->meta_page)); + flush_kernel_vmap_range(cpu_buffer->meta_page, PAGE_SIZE); } static void @@ -7319,7 +7319,8 @@ consume: out: /* Some archs do not have data cache coherency between kernel and user-space */ - flush_dcache_folio(virt_to_folio(cpu_buffer->reader_page->page)); + flush_kernel_vmap_range(cpu_buffer->reader_page->page, + buffer->subbuf_size + BUF_PAGE_HDR_SIZE); rb_update_meta_page(cpu_buffer); diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index d058b519d502..b581e388a9d9 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -50,6 +50,7 @@ #include <linux/irq_work.h> #include <linux/workqueue.h> #include <linux/sort.h> +#include <linux/io.h> /* vmap_page_range() */ #include <asm/setup.h> /* COMMAND_LINE_SIZE */ @@ -8500,6 +8501,10 @@ static int tracing_buffers_mmap(struct file *filp, struct vm_area_struct *vma) struct trace_iterator *iter = &info->iter; int ret = 0; + /* A memmap'ed buffer is not supported for user space mmap */ + if (iter->tr->flags & TRACE_ARRAY_FL_MEMMAP) + return -ENODEV; + /* Currently the boot mapped buffer is not supported for mmap */ if (iter->tr->flags & TRACE_ARRAY_FL_BOOT) return -ENODEV; @@ -9609,9 +9614,6 @@ static void free_trace_buffers(struct trace_array *tr) #ifdef CONFIG_TRACER_MAX_TRACE free_trace_buffer(&tr->max_buffer); #endif - - if (tr->range_addr_start) - vunmap((void *)tr->range_addr_start); } static void init_trace_flags_index(struct trace_array *tr) @@ -9804,29 +9806,27 @@ static int instance_mkdir(const char *name) return ret; } -static u64 map_pages(u64 start, u64 size) +static u64 map_pages(unsigned long start, unsigned long size) { - struct page **pages; - phys_addr_t page_start; - unsigned int page_count; - unsigned int i; - void *vaddr; - - page_count = DIV_ROUND_UP(size, PAGE_SIZE); + unsigned long vmap_start, vmap_end; + struct vm_struct *area; + int ret; - page_start = start; - pages = kmalloc_array(page_count, sizeof(struct page *), GFP_KERNEL); - if (!pages) + area = get_vm_area(size, VM_IOREMAP); + if (!area) return 0; - for (i = 0; i < page_count; i++) { - phys_addr_t addr = page_start + i * PAGE_SIZE; - pages[i] = pfn_to_page(addr >> PAGE_SHIFT); + vmap_start = (unsigned long) area->addr; + vmap_end = vmap_start + size; + + ret = vmap_page_range(vmap_start, vmap_end, + start, pgprot_nx(PAGE_KERNEL)); + if (ret < 0) { + free_vm_area(area); + return 0; } - vaddr = vmap(pages, page_count, VM_MAP, PAGE_KERNEL); - kfree(pages); - return (u64)(unsigned long)vaddr; + return (u64)vmap_start; } /** @@ -10705,6 +10705,7 @@ static inline void do_allocate_snapshot(const char *name) { } __init static void enable_instances(void) { struct trace_array *tr; + bool memmap_area = false; char *curr_str; char *name; char *str; @@ -10773,6 +10774,7 @@ __init static void enable_instances(void) name); continue; } + memmap_area = true; } else if (tok) { if (!reserve_mem_find_by_name(tok, &start, &size)) { start = 0; @@ -10783,7 +10785,20 @@ __init static void enable_instances(void) } if (start) { - addr = map_pages(start, size); + /* Start and size must be page aligned */ + if (start & ~PAGE_MASK) { + pr_warn("Tracing: mapping start addr %pa is not page aligned\n", &start); + continue; + } + if (size & ~PAGE_MASK) { + pr_warn("Tracing: mapping size %pa is not page aligned\n", &size); + continue; + } + + if (memmap_area) + addr = map_pages(start, size); + else + addr = (unsigned long)phys_to_virt(start); if (addr) { pr_info("Tracing: mapped boot instance %s at physical memory %pa of size 0x%lx\n", name, &start, (unsigned long)size); @@ -10810,10 +10825,13 @@ __init static void enable_instances(void) update_printk_trace(tr); /* - * If start is set, then this is a mapped buffer, and - * cannot be deleted by user space, so keep the reference - * to it. + * memmap'd buffers can not be freed. */ + if (memmap_area) { + tr->flags |= TRACE_ARRAY_FL_MEMMAP; + tr->ref++; + } + if (start) { tr->flags |= TRACE_ARRAY_FL_BOOT | TRACE_ARRAY_FL_LAST_BOOT; tr->range_name = no_free_ptr(rname); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index f4f859d69bcf..79be1995db44 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -447,6 +447,7 @@ enum { TRACE_ARRAY_FL_BOOT = BIT(1), TRACE_ARRAY_FL_LAST_BOOT = BIT(2), TRACE_ARRAY_FL_MOD_INIT = BIT(3), + TRACE_ARRAY_FL_MEMMAP = BIT(4), }; #ifdef CONFIG_MODULES |