Merge tag 'x86-urgent-2021-11-21' of git://git.kernel.org/pub/scm/linux/kernel/git...

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

diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 63d3de0..8471a8b 100644 (file)
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -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,

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 49b596d..c410be7 100644 (file)
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -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