Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux into master

Pull arm64 fixes from Will Deacon:
 "A batch of arm64 fixes.

  Although the diffstat is a bit larger than we'd usually have at this
  stage, a decent amount of it is the addition of comments describing
  our syscall tracing behaviour, and also a sweep across all the modular
  arm64 PMU drivers to make them rebust against unloading and unbinding.

  There are a couple of minor things kicking around at the moment (CPU
  errata and module PLTs for very large modules), but I'm not expecting
  any significant changes now for us in 5.8.

   - Fix kernel text addresses for relocatable images booting using EFI
     and with KASLR disabled so that they match the vmlinux ELF binary.

   - Fix unloading and unbinding of PMU driver modules.

   - Fix generic mmiowb() when writeX() is called from preemptible
     context (reported by the riscv folks).

   - Fix ptrace hardware single-step interactions with signal handlers,
     system calls and reverse debugging.

   - Fix reporting of 64-bit x0 register for 32-bit tasks via
     'perf_regs'.

   - Add comments describing syscall entry/exit tracing ABI"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  drivers/perf: Prevent forced unbinding of PMU drivers
  asm-generic/mmiowb: Allow mmiowb_set_pending() when preemptible()
  arm64: Use test_tsk_thread_flag() for checking TIF_SINGLESTEP
  arm64: ptrace: Use NO_SYSCALL instead of -1 in syscall_trace_enter()
  arm64: syscall: Expand the comment about ptrace and syscall(-1)
  arm64: ptrace: Add a comment describing our syscall entry/exit trap ABI
  arm64: compat: Ensure upper 32 bits of x0 are zero on syscall return
  arm64: ptrace: Override SPSR.SS when single-stepping is enabled
  arm64: ptrace: Consistently use pseudo-singlestep exceptions
  drivers/perf: Fix kernel panic when rmmod PMU modules during perf sampling
  efi/libstub/arm64: Retain 2MB kernel Image alignment if !KASLR

2 files changed, 15 insertions, 12 deletions

diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c
index 7f6a57dec513..e5bfac79e5ac 100644
--- a/drivers/firmware/efi/libstub/arm64-stub.c
+++ b/drivers/firmware/efi/libstub/arm64-stub.c
@@ -35,13 +35,16 @@ efi_status_t check_platform_features(void)
 }
 
 /*
- * Relocatable kernels can fix up the misalignment with respect to
- * MIN_KIMG_ALIGN, so they only require a minimum alignment of EFI_KIMG_ALIGN
- * (which accounts for the alignment of statically allocated objects such as
- * the swapper stack.)
+ * Although relocatable kernels can fix up the misalignment with respect to
+ * MIN_KIMG_ALIGN, the resulting virtual text addresses are subtly out of
+ * sync with those recorded in the vmlinux when kaslr is disabled but the
+ * image required relocation anyway. Therefore retain 2M alignment unless
+ * KASLR is in use.
  */
-static const u64 min_kimg_align = IS_ENABLED(CONFIG_RELOCATABLE) ? EFI_KIMG_ALIGN
-								 : MIN_KIMG_ALIGN;
+static u64 min_kimg_align(void)
+{
+	return efi_nokaslr ? MIN_KIMG_ALIGN : EFI_KIMG_ALIGN;
+}
 
 efi_status_t handle_kernel_image(unsigned long *image_addr,
 				 unsigned long *image_size,
@@ -74,21 +77,21 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
 
 	kernel_size = _edata - _text;
 	kernel_memsize = kernel_size + (_end - _edata);
-	*reserve_size = kernel_memsize + TEXT_OFFSET % min_kimg_align;
+	*reserve_size = kernel_memsize + TEXT_OFFSET % min_kimg_align();
 
 	if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && phys_seed != 0) {
 		/*
 		 * If KASLR is enabled, and we have some randomness available,
 		 * locate the kernel at a randomized offset in physical memory.
 		 */
-		status = efi_random_alloc(*reserve_size, min_kimg_align,
+		status = efi_random_alloc(*reserve_size, min_kimg_align(),
 					  reserve_addr, phys_seed);
 	} else {
 		status = EFI_OUT_OF_RESOURCES;
 	}
 
 	if (status != EFI_SUCCESS) {
-		if (IS_ALIGNED((u64)_text - TEXT_OFFSET, min_kimg_align)) {
+		if (IS_ALIGNED((u64)_text - TEXT_OFFSET, min_kimg_align())) {
 			/*
 			 * Just execute from wherever we were loaded by the
 			 * UEFI PE/COFF loader if the alignment is suitable.
@@ -99,7 +102,7 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
 		}
 
 		status = efi_allocate_pages_aligned(*reserve_size, reserve_addr,
-						    ULONG_MAX, min_kimg_align);
+						    ULONG_MAX, min_kimg_align());
 
 		if (status != EFI_SUCCESS) {
 			efi_err("Failed to relocate kernel\n");
@@ -108,7 +111,7 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
 		}
 	}
 
-	*image_addr = *reserve_addr + TEXT_OFFSET % min_kimg_align;
+	*image_addr = *reserve_addr + TEXT_OFFSET % min_kimg_align();
 	memcpy((void *)*image_addr, _text, kernel_size);
 
 	return EFI_SUCCESS;
diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c
index d40fd68c6bb2..6bca70bbb43d 100644
--- a/drivers/firmware/efi/libstub/efi-stub-helper.c
+++ b/drivers/firmware/efi/libstub/efi-stub-helper.c
@@ -19,7 +19,7 @@
 #include "efistub.h"
 
 bool efi_nochunk;
-bool efi_nokaslr;
+bool efi_nokaslr = !IS_ENABLED(CONFIG_RANDOMIZE_BASE);
 bool efi_noinitrd;
 int efi_loglevel = CONSOLE_LOGLEVEL_DEFAULT;
 bool efi_novamap;