Commit 628d06a4 authored by Sami Tolvanen's avatar Sami Tolvanen Committed by Will Deacon
Browse files

scs: Add page accounting for shadow call stack allocations 



This change adds accounting for the memory allocated for shadow stacks.

Signed-off-by: default avatarSami Tolvanen <samitolvanen@google.com>
Reviewed-by: default avatarKees Cook <keescook@chromium.org>
Acked-by: default avatarWill Deacon <will@kernel.org>
Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent d08b9f0c

drivers/base/node.c

+6 −0
Original line number Diff line number Diff line
@@ -415,6 +415,9 @@ static ssize_t node_read_meminfo(struct device *dev, 
		       "Node %d AnonPages:      %8lu kB\n"

		       "Node %d Shmem:          %8lu kB\n"

		       "Node %d KernelStack:    %8lu kB\n"

#ifdef CONFIG_SHADOW_CALL_STACK

		       "Node %d ShadowCallStack:%8lu kB\n"

#endif

		       "Node %d PageTables:     %8lu kB\n"

		       "Node %d NFS_Unstable:   %8lu kB\n"

		       "Node %d Bounce:         %8lu kB\n"
@@ -438,6 +441,9 @@ static ssize_t node_read_meminfo(struct device *dev, 
		       nid, K(node_page_state(pgdat, NR_ANON_MAPPED)),

		       nid, K(i.sharedram),

		       nid, sum_zone_node_page_state(nid, NR_KERNEL_STACK_KB),

#ifdef CONFIG_SHADOW_CALL_STACK

		       nid, sum_zone_node_page_state(nid, NR_KERNEL_SCS_KB),

#endif

		       nid, K(sum_zone_node_page_state(nid, NR_PAGETABLE)),

		       nid, K(node_page_state(pgdat, NR_UNSTABLE_NFS)),

		       nid, K(sum_zone_node_page_state(nid, NR_BOUNCE)),

fs/proc/meminfo.c

+4 −0
Original line number Diff line number Diff line
@@ -103,6 +103,10 @@ static int meminfo_proc_show(struct seq_file *m, void *v) 
	show_val_kb(m, "SUnreclaim:     ", sunreclaim);

	seq_printf(m, "KernelStack:    %8lu kB\n",

		   global_zone_page_state(NR_KERNEL_STACK_KB));

#ifdef CONFIG_SHADOW_CALL_STACK

	seq_printf(m, "ShadowCallStack:%8lu kB\n",

		   global_zone_page_state(NR_KERNEL_SCS_KB));

#endif

	show_val_kb(m, "PageTables:     ",

		    global_zone_page_state(NR_PAGETABLE));

include/linux/mmzone.h

+3 −0
Original line number Diff line number Diff line
@@ -156,6 +156,9 @@ enum zone_stat_item { 
	NR_MLOCK,		/* mlock()ed pages found and moved off LRU */

	NR_PAGETABLE,		/* used for pagetables */

	NR_KERNEL_STACK_KB,	/* measured in KiB */

#if IS_ENABLED(CONFIG_SHADOW_CALL_STACK)

	NR_KERNEL_SCS_KB,	/* measured in KiB */

#endif

	/* Second 128 byte cacheline */

	NR_BOUNCE,

#if IS_ENABLED(CONFIG_ZSMALLOC)

kernel/scs.c

+15 −0
Original line number Diff line number Diff line
@@ -6,8 +6,10 @@ 
 */



#include <linux/kasan.h>

#include <linux/mm.h>

#include <linux/scs.h>

#include <linux/slab.h>

#include <linux/vmstat.h>

#include <asm/scs.h>



static struct kmem_cache *scs_cache;
@@ -40,6 +42,17 @@ void __init scs_init(void) 
	scs_cache = kmem_cache_create("scs_cache", SCS_SIZE, 0, 0, NULL);

}



static struct page *__scs_page(struct task_struct *tsk)

{

	return virt_to_page(task_scs(tsk));

}



static void scs_account(struct task_struct *tsk, int account)

{

	mod_zone_page_state(page_zone(__scs_page(tsk)), NR_KERNEL_SCS_KB,

		account * (SCS_SIZE / 1024));

}



int scs_prepare(struct task_struct *tsk, int node)

{

	void *s = scs_alloc(node);
@@ -49,6 +62,7 @@ int scs_prepare(struct task_struct *tsk, int node) 


	task_scs(tsk) = s;

	task_scs_offset(tsk) = 0;

	scs_account(tsk, 1);



	return 0;

}
@@ -61,5 +75,6 @@ void scs_release(struct task_struct *tsk) 
		return;



	WARN(scs_corrupted(tsk), "corrupted shadow stack detected when freeing task\n");

	scs_account(tsk, -1);

	scs_free(s);

}

mm/page_alloc.c

+6 −0
Original line number Diff line number Diff line
@@ -5411,6 +5411,9 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask) 
			" managed:%lukB"

			" mlocked:%lukB"

			" kernel_stack:%lukB"

#ifdef CONFIG_SHADOW_CALL_STACK

			" shadow_call_stack:%lukB"

#endif

			" pagetables:%lukB"

			" bounce:%lukB"

			" free_pcp:%lukB"
@@ -5433,6 +5436,9 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask) 
			K(zone_managed_pages(zone)),

			K(zone_page_state(zone, NR_MLOCK)),

			zone_page_state(zone, NR_KERNEL_STACK_KB),

#ifdef CONFIG_SHADOW_CALL_STACK

			zone_page_state(zone, NR_KERNEL_SCS_KB),

#endif

			K(zone_page_state(zone, NR_PAGETABLE)),

			K(zone_page_state(zone, NR_BOUNCE)),

			K(free_pcp),