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Date: Fri, 22 Mar 2019 16:34:19 +0800 From: Baoquan He <bhe@...hat.com> To: Pingfan Liu <kernelfans@...il.com>, dyoung@...hat.com Cc: x86@...nel.org, Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, "H. Peter Anvin" <hpa@...or.com>, Will Deacon <will.deacon@....com>, Nicolas Pitre <nico@...aro.org>, Chao Fan <fanc.fnst@...fujitsu.com>, "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>, Ard Biesheuvel <ard.biesheuvel@...aro.org>, LKML <linux-kernel@...r.kernel.org> Subject: Re: [PATCHv2] x86/boot/KASLR: skip the specified crashkernel reserved region On 03/22/19 at 03:52pm, Baoquan He wrote: > On 03/22/19 at 03:43pm, Pingfan Liu wrote: > > > > +/* parse crashkernel=x@y option */ > > > > +static void mem_avoid_crashkernel_simple(char *option) > > > > > > Chao ever mentioned this, I want to ask again, why does it has to be > > > xxx_simple()? > > > > > Seems that I had replied Chao's question in another email. The naming > > follows the function parse_crashkernel_simple(), as the notes above > ~~~~~~~~~~~~~~~~~~~~~~~~ > > Sorry, I don't get. typo? OK, I misunderstood it. We do have parse_crashkernel_simple() to handle crashkernel=size[@offset] case, to differente with other complicated cases, like crashkernel=size,[high|low], Then I am fine with this naming. Soryy about the noise. By the way, do you think if we should take care of this case: crashkernel=<range1>:<size1>[,<range2>:<size2>,...][@offset] It can also specify @offset. Not sure if it's too complicated, you may have a investigation. These two cases have dependency on your crashkernel=X bug fix patch. The current code only allow crashkernel= to reserve under 896MB. I noticed Boris has agreed on the solution. Maybe you can repost a new version based on the discussion. http://lkml.kernel.org/r/1548047768-7656-1-git-send-email-kernelfans@gmail.com [PATCHv7] x86/kdump: bugfix, make the behavior of crashkernel=X consistent with kaslr Thanks Baoquan > > > the definition > > /* > > * That function parses "simple" (old) crashkernel command lines like > > * > > * crashkernel=size[@offset] > > Hmm, should only crashkernel=size@...set be cared? crashkernel=size will > auto finding a place to reserve, and that is after KASLR. > > > * > > * It returns 0 on success and -EINVAL on failure. > > */ > > static int __init parse_crashkernel_simple(char *cmdline, > > > > Do you have alternative suggestion? > > > > > Except of these, patch looks good to me. It's a nice catch, and only > > > need a simple fix based on the current code. > > > > > Thank you for the kindly review. > > > > Regards, > > Pingfan > > > > > Thanks > > > Baoquan > > > > > > > +{ > > > > + unsigned long long crash_size, crash_base; > > > > + char *cur = option; > > > > + > > > > + crash_size = memparse(option, &cur); > > > > + if (option == cur) > > > > + return; > > > > + > > > > + if (*cur == '@') { > > > > + option = cur + 1; > > > > + crash_base = memparse(option, &cur); > > > > + if (option == cur) > > > > + return; > > > > + mem_avoid[MEM_AVOID_CRASHKERNEL].start = crash_base; > > > > + mem_avoid[MEM_AVOID_CRASHKERNEL].size = crash_size; > > > > + } > > > > +} > > > > > > > > static void handle_mem_options(void) > > > > { > > > > @@ -250,7 +270,7 @@ static void handle_mem_options(void) > > > > u64 mem_size; > > > > > > > > if (!strstr(args, "memmap=") && !strstr(args, "mem=") && > > > > - !strstr(args, "hugepages")) > > > > + !strstr(args, "hugepages") && !strstr(args, "crashkernel=")) > > > > return; > > > > > > > > tmp_cmdline = malloc(len + 1); > > > > @@ -286,6 +306,8 @@ static void handle_mem_options(void) > > > > goto out; > > > > > > > > mem_limit = mem_size; > > > > + } else if (strstr(param, "crashkernel")) { > > > > + mem_avoid_crashkernel_simple(val); > > > > } > > > > } > > > > > > > > @@ -414,7 +436,7 @@ 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 */ > > > > + /* Mark the regions we need to avoid */ > > > > handle_mem_options(); > > > > > > > > #ifdef CONFIG_X86_VERBOSE_BOOTUP > > > > -- > > > > 2.7.4 > > > >
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