From: Baoquan He <bhe@redhat.com>
To: Chao Fan <fanc.fnst@cn.fujitsu.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com,
tglx@linutronix.de, mingo@redhat.com, keescook@chromium.org,
yasu.isimatu@gmail.com, indou.takao@jp.fujitsu.com,
lcapitulino@redhat.com
Subject: Re: [PATCH v7 1/5] x86/KASLR: Add kaslr_mem=nn[KMG]@ss[KMG]
Date: Fri, 19 Jan 2018 10:34:05 +0800 [thread overview]
Message-ID: <20180119023405.GA1753@localhost.localdomain> (raw)
In-Reply-To: <20180117105351.12226-2-fanc.fnst@cn.fujitsu.com>
On 01/17/18 at 06:53pm, Chao Fan wrote:
> Introduce a new kernel parameter kaslr_mem=nn[KMG]@ss[KMG] which is used
> by KASLR only during kernel decompression stage.
>
> Users can use it to specify memory regions where kernel can be randomized
> into. E.g if movable_node specified in kernel cmdline, kernel could be
~ remove 'into'
> extracted into those movable regions, this will make memory hotplug fail.
> With the help of 'kaslr_mem=', limit kernel in those immovable regions
> specified.
>
> Signed-off-by: Chao Fan <fanc.fnst@cn.fujitsu.com>
> ---
> arch/x86/boot/compressed/kaslr.c | 73 ++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 70 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
> index 8199a6187251..b21741135673 100644
> --- a/arch/x86/boot/compressed/kaslr.c
> +++ b/arch/x86/boot/compressed/kaslr.c
> @@ -108,6 +108,15 @@ enum mem_avoid_index {
>
> static struct mem_vector mem_avoid[MEM_AVOID_MAX];
>
> +/* Only support at most 4 usable memory regions specified for kaslr */
> +#define MAX_KASLR_MEM_USABLE 4
> +
> +/* Store the usable memory regions for kaslr */
> +static struct mem_vector mem_usable[MAX_KASLR_MEM_USABLE];
The name xx_usable sounds not so good, while I don't know what
is better. Otherwise this patch looks good to me.
Ack it.
Acked-by: Baoquan He <bhe@redhat.com>
> +
> +/* The amount of usable regions for kaslr user specify, not more than 4 */
> +static int num_usable_region;
> +
> static bool mem_overlaps(struct mem_vector *one, struct mem_vector *two)
> {
> /* Item one is entirely before item two. */
> @@ -206,7 +215,62 @@ static void mem_avoid_memmap(char *str)
> memmap_too_large = true;
> }
>
> -static int handle_mem_memmap(void)
> +static int parse_kaslr_mem(char *p,
> + unsigned long long *start,
> + unsigned long long *size)
> +{
> + char *oldp;
> +
> + if (!p)
> + return -EINVAL;
> +
> + oldp = p;
> + *size = memparse(p, &p);
> + if (p == oldp)
> + return -EINVAL;
> +
> + switch (*p) {
> + case '@':
> + *start = memparse(p + 1, &p);
> + return 0;
> + default:
> + /*
> + * If w/o offset, only size specified, kaslr_mem=nn[KMG]
> + * has the same behaviour as kaslr_mem=nn[KMG]@0. It means
> + * the region starts from 0.
> + */
> + *start = 0;
> + return 0;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static void parse_kaslr_mem_regions(char *str)
> +{
> + static int i;
> +
> + while (str && (i < MAX_KASLR_MEM_USABLE)) {
> + int rc;
> + unsigned long long start, size;
> + char *k = strchr(str, ',');
> +
> + if (k)
> + *k++ = 0;
> +
> + rc = parse_kaslr_mem(str, &start, &size);
> + if (rc < 0)
> + break;
> + str = k;
> +
> + mem_usable[i].start = start;
> + mem_usable[i].size = size;
> + i++;
> + }
> + num_usable_region = i;
> +}
> +
> +static int handle_mem_filter(void)
> {
> char *args = (char *)get_cmd_line_ptr();
> size_t len = strlen((char *)args);
> @@ -214,7 +278,8 @@ static int handle_mem_memmap(void)
> char *param, *val;
> u64 mem_size;
>
> - if (!strstr(args, "memmap=") && !strstr(args, "mem="))
> + if (!strstr(args, "memmap=") && !strstr(args, "mem=") &&
> + !strstr(args, "kaslr_mem="))
> return 0;
>
> tmp_cmdline = malloc(len + 1);
> @@ -239,6 +304,8 @@ static int handle_mem_memmap(void)
>
> if (!strcmp(param, "memmap")) {
> mem_avoid_memmap(val);
> + } else if (!strcmp(param, "kaslr_mem")) {
> + parse_kaslr_mem_regions(val);
> } else if (!strcmp(param, "mem")) {
> char *p = val;
>
> @@ -378,7 +445,7 @@ static void mem_avoid_init(unsigned long input, unsigned long input_size,
> /* We don't need to set a mapping for setup_data. */
>
> /* Mark the memmap regions we need to avoid */
> - handle_mem_memmap();
> + handle_mem_filter();
>
> #ifdef CONFIG_X86_VERBOSE_BOOTUP
> /* Make sure video RAM can be used. */
> --
> 2.14.3
>
>
>
next prev parent reply other threads:[~2018-01-19 2:34 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-17 10:53 [PATCH v7 0/5] x86/KASLR: Add parameter kaslr_mem=nn[KMG]@ss[KMG] Chao Fan
2018-01-17 10:53 ` [PATCH v7 1/5] x86/KASLR: Add kaslr_mem=nn[KMG]@ss[KMG] Chao Fan
2018-01-19 2:34 ` Baoquan He [this message]
2018-01-17 10:53 ` [PATCH v7 2/5] x86/KASLR: Handle the memory regions specified in kaslr_mem Chao Fan
2018-01-19 2:39 ` Baoquan He
2018-01-17 10:53 ` [PATCH v7 3/5] x86/KASLR: Give a warning if movable_node specified without kaslr_mem= Chao Fan
2018-01-17 14:02 ` Baoquan He
2018-01-18 1:20 ` Chao Fan
2018-01-17 14:04 ` Baoquan He
2018-01-19 3:31 ` [PATCH v8 " Chao Fan
2018-01-19 3:48 ` Baoquan He
2018-01-17 10:53 ` [PATCH v7 4/5] x86/KASLR: Skip memory mirror handling if movable_node specified Chao Fan
2018-01-17 14:03 ` Baoquan He
2018-01-18 1:13 ` Chao Fan
2018-01-19 3:33 ` [PATCH v8 " Chao Fan
2018-01-19 3:47 ` Baoquan He
2018-01-17 10:53 ` [PATCH v7 5/5] document: add document for kaslr_mem Chao Fan
2018-01-19 3:00 ` Baoquan He
2018-01-19 3:36 ` [PATCH v8 " Chao Fan
2018-01-19 3:53 ` Baoquan He
2018-01-19 5:27 ` Chao Fan
2018-01-19 5:23 ` [RESEND PATCH " Chao Fan
2018-01-19 18:20 ` Randy Dunlap
2018-01-17 17:32 ` [PATCH v7 0/5] x86/KASLR: Add parameter kaslr_mem=nn[KMG]@ss[KMG] Luiz Capitulino
2018-01-18 1:11 ` Chao Fan
2018-01-18 13:39 ` Luiz Capitulino
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