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Two X86 fixes:

Browse Source 
- Move the command line preparation and the early command line parsing
    earlier so that the command line parameters which affect
    early_reserve_memory(), e.g. efi=nosftreserve, are taken into
    account. This was broken when the invocation of early_reserve_memory()
    was moved recently.
 
  - Use an atomic type for the SGX page accounting, which is read and
    written lockless, to plug various race conditions related to it.
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Merge tag 'x86-urgent-2021-11-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Thomas Gleixner:

 - Move the command line preparation and the early command line parsing
   earlier so that the command line parameters which affect
   early_reserve_memory(), e.g. efi=nosftreserve, are taken into
   account. This was broken when the invocation of
   early_reserve_memory() was moved recently.

 - Use an atomic type for the SGX page accounting, which is read and
   written locklessly, to plug various race conditions related to it.

* tag 'x86-urgent-2021-11-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/sgx: Fix free page accounting
  x86/boot: Pull up cmdline preparation and early param parsing
This commit is contained in:
Linus Torvalds 2021-11-21 11:25:19 -08:00
commit 40c93d7fff
2 changed files with 45 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
arch/x86/kernel/cpu/sgx/main.c
View File

@ -28,8 +28,7 @@ static DECLARE_WAIT_QUEUE_HEAD(ksgxd_waitq);
static LIST_HEAD(sgx_active_page_list);
static DEFINE_SPINLOCK(sgx_reclaimer_lock);
/* The free page list lock protected variables prepend the lock. */
static unsigned long sgx_nr_free_pages;
static atomic_long_t sgx_nr_free_pages = ATOMIC_LONG_INIT(0);
/* Nodes with one or more EPC sections. */
static nodemask_t sgx_numa_mask;
@ -403,14 +402,15 @@ skip:
spin_lock(&node->lock);
list_add_tail(&epc_page->list, &node->free_page_list);
sgx_nr_free_pages++;
spin_unlock(&node->lock);
atomic_long_inc(&sgx_nr_free_pages);
}
}
static bool sgx_should_reclaim(unsigned long watermark)
{
return sgx_nr_free_pages < watermark && !list_empty(&sgx_active_page_list);
return atomic_long_read(&sgx_nr_free_pages) < watermark &&
!list_empty(&sgx_active_page_list);
}
static int ksgxd(void *p)
@ -471,9 +471,9 @@ static struct sgx_epc_page *__sgx_alloc_epc_page_from_node(int nid)
page = list_first_entry(&node->free_page_list, struct sgx_epc_page, list);
list_del_init(&page->list);
sgx_nr_free_pages--;
spin_unlock(&node->lock);
atomic_long_dec(&sgx_nr_free_pages);
return page;
}
@ -625,9 +625,9 @@ void sgx_free_epc_page(struct sgx_epc_page *page)
spin_lock(&node->lock);
list_add_tail(&page->list, &node->free_page_list);
sgx_nr_free_pages++;
spin_unlock(&node->lock);
atomic_long_inc(&sgx_nr_free_pages);
}
static bool __init sgx_setup_epc_section(u64 phys_addr, u64 size,

66
arch/x86/kernel/setup.c
View File

@ -742,6 +742,28 @@ dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p)
return 0;
}
static char *prepare_command_line(void)
{
#ifdef CONFIG_CMDLINE_BOOL
#ifdef CONFIG_CMDLINE_OVERRIDE
strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
#else
if (builtin_cmdline[0]) {
/* append boot loader cmdline to builtin */
strlcat(builtin_cmdline, " ", COMMAND_LINE_SIZE);
strlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE);
strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
}
#endif
#endif
strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
parse_early_param();
return command_line;
}
/*
* Determine if we were loaded by an EFI loader. If so, then we have also been
* passed the efi memmap, systab, etc., so we should use these data structures
@ -830,6 +852,23 @@ void __init setup_arch(char **cmdline_p)
x86_init.oem.arch_setup();
/*
* x86_configure_nx() is called before parse_early_param() (called by
* prepare_command_line()) to detect whether hardware doesn't support
* NX (so that the early EHCI debug console setup can safely call
* set_fixmap()). It may then be called again from within noexec_setup()
* during parsing early parameters to honor the respective command line
* option.
*/
x86_configure_nx();
/*
* This parses early params and it needs to run before
* early_reserve_memory() because latter relies on such settings
* supplied as early params.
*/
*cmdline_p = prepare_command_line();
/*
* Do some memory reservations *before* memory is added to memblock, so
* memblock allocations won't overwrite it.
@ -863,33 +902,6 @@ void __init setup_arch(char **cmdline_p)
bss_resource.start = __pa_symbol(__bss_start);
bss_resource.end = __pa_symbol(__bss_stop)-1;
#ifdef CONFIG_CMDLINE_BOOL
#ifdef CONFIG_CMDLINE_OVERRIDE
strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
#else
if (builtin_cmdline[0]) {
/* append boot loader cmdline to builtin */
strlcat(builtin_cmdline, " ", COMMAND_LINE_SIZE);
strlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE);
strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
}
#endif
#endif
strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
*cmdline_p = command_line;
/*
* x86_configure_nx() is called before parse_early_param() to detect
* whether hardware doesn't support NX (so that the early EHCI debug
* console setup can safely call set_fixmap()). It may then be called
* again from within noexec_setup() during parsing early parameters
* to honor the respective command line option.
*/
x86_configure_nx();
parse_early_param();
#ifdef CONFIG_MEMORY_HOTPLUG
/*
* Memory used by the kernel cannot be hot-removed because Linux