On Wed, Apr 24, 2019 at 04:47:11PM +0300, Mike Rapoport wrote: > On Wed, Apr 24, 2019 at 01:47:46AM +0300, Serge Semin wrote: > > It is useful at least for debugging to have the kernel virtual > > memory layout printed at boot time so to have the full information > > about the booted kernel. Make the printing optional and available > > only when DEBUG_KERNEL config is enabled so not to leak a sensitive > > kernel information. > > > > Signed-off-by: Serge Semin <[email protected]> > > --- > > arch/mips/mm/init.c | 49 +++++++++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 49 insertions(+) > > > > diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c > > index bbb196ad5f26..c338bbd03b2a 100644 > > --- a/arch/mips/mm/init.c > > +++ b/arch/mips/mm/init.c > > @@ -31,6 +31,7 @@ > > #include <linux/gfp.h> > > #include <linux/kcore.h> > > #include <linux/initrd.h> > > +#include <linux/sizes.h> > > > > #include <asm/bootinfo.h> > > #include <asm/cachectl.h> > > @@ -56,6 +57,53 @@ unsigned long empty_zero_page, zero_page_mask; > > EXPORT_SYMBOL_GPL(empty_zero_page); > > EXPORT_SYMBOL(zero_page_mask); > > > > +/* > > + * Print out the kernel virtual memory layout > > + */ > > +#define MLK(b, t) (void *)b, (void *)t, ((t) - (b)) >> 10 > > +#define MLM(b, t) (void *)b, (void *)t, ((t) - (b)) >> 20 > > +#define MLK_ROUNDUP(b, t) (void *)b, (void *)t, DIV_ROUND_UP(((t) - (b)), > > SZ_1K) > > +static void __init mem_print_kmap_info(void) > > +{ > > +#ifdef CONFIG_DEBUG_KERNEL > > Maybe CONFIG_DEBUG_VM? >
Last time I posted this patch Matt suggested to use CONFIG_DEBUG_KERNEL [1]. On the other hand arm platform prints this table unconditionally, but uses %lx format for low-memory ranges and %p for kernel segments. I even more inclined in the arm solution. But if selecting between DEBUG_KERNEL and DEBUG_VM I'd stick with DEBUG_KERNEL, since VM-debug config help text states it is intended for special performance checks: "Enable this to turn on extended checks in the virtual-memory system that may impact performance," and not for memory layout. -Sergey [1] https://lkml.org/lkml/2018/2/13/494 > > + pr_notice("Kernel virtual memory layout:\n" > > + " lowmem : 0x%px - 0x%px (%4ld MB)\n" > > + " .text : 0x%px - 0x%px (%4td kB)\n" > > + " .data : 0x%px - 0x%px (%4td kB)\n" > > + " .init : 0x%px - 0x%px (%4td kB)\n" > > + " .bss : 0x%px - 0x%px (%4td kB)\n" > > + " vmalloc : 0x%px - 0x%px (%4ld MB)\n" > > +#ifdef CONFIG_HIGHMEM > > + " pkmap : 0x%px - 0x%px (%4ld MB)\n" > > +#endif > > + " fixmap : 0x%px - 0x%px (%4ld kB)\n", > > + MLM(PAGE_OFFSET, (unsigned long)high_memory), > > + MLK_ROUNDUP(_text, _etext), > > + MLK_ROUNDUP(_sdata, _edata), > > + MLK_ROUNDUP(__init_begin, __init_end), > > + MLK_ROUNDUP(__bss_start, __bss_stop), > > + MLM(VMALLOC_START, VMALLOC_END), > > +#ifdef CONFIG_HIGHMEM > > + MLM(PKMAP_BASE, (PKMAP_BASE) + (LAST_PKMAP)*(PAGE_SIZE)), > > +#endif > > + MLK(FIXADDR_START, FIXADDR_TOP)); > > + > > + /* Check some fundamental inconsistencies. May add something else? */ > > +#ifdef CONFIG_HIGHMEM > > + BUILD_BUG_ON(VMALLOC_END < PAGE_OFFSET); > > + BUG_ON(VMALLOC_END < (unsigned long)high_memory); > > + BUILD_BUG_ON((PKMAP_BASE) + (LAST_PKMAP)*(PAGE_SIZE) < PAGE_OFFSET); > > + BUG_ON((PKMAP_BASE) + (LAST_PKMAP)*(PAGE_SIZE) < > > + (unsigned long)high_memory); > > +#endif > > + BUILD_BUG_ON(FIXADDR_TOP < PAGE_OFFSET); > > + BUG_ON(FIXADDR_TOP < (unsigned long)high_memory); > > +#endif /* CONFIG_DEBUG_KERNEL */ > > +} > > +#undef MLK > > +#undef MLM > > +#undef MLK_ROUNDUP > > + > > /* > > * Not static inline because used by IP27 special magic initialization code > > */ > > @@ -479,6 +527,7 @@ void __init mem_init(void) > > setup_zero_pages(); /* Setup zeroed pages. */ > > mem_init_free_highmem(); > > mem_init_print_info(NULL); > > + mem_print_kmap_info(); > > > > #ifdef CONFIG_64BIT > > if ((unsigned long) &_text > (unsigned long) CKSEG0) > > -- > > 2.21.0 > > > > -- > Sincerely yours, > Mike. >
