Drop um-fix-stack-pointer-alignment.patch from 5.10

Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/queue-5.10/series b/queue-5.10/series
index 1ab37360272fc5da93132c9c1dd42fd9a8167f8c..0adbdf440a31f6504834bcc9c061fb38b4b890dd 100644 (file)
--- a/queue-5.10/series
+++ b/queue-5.10/series
@@ -154,7 +154,6 @@ power-supply-rt5033_battery-fix-device-tree-enumerat.patch
 nfsv4-initialise-connection-to-the-server-in-nfs4_al.patch
 nfsv4-fix-an-oops-in-pnfs_mark_request_commit-when-d.patch
 misc-alcor_pci-fix-inverted-branch-condition.patch
-um-fix-stack-pointer-alignment.patch
 um-fix-error-return-code-in-slip_open.patch
 um-fix-error-return-code-in-winch_tramp.patch
 ubifs-fix-off-by-one-error.patch

diff --git a/queue-5.10/um-fix-stack-pointer-alignment.patch b/queue-5.10/um-fix-stack-pointer-alignment.patch
deleted file mode 100644 (file)
index 13662be..0000000
--- a/queue-5.10/um-fix-stack-pointer-alignment.patch
+++ /dev/null
@@ -1,174 +0,0 @@
-From 06f5002541afb817adaa62fcf53fc44cb9110071 Mon Sep 17 00:00:00 2001
-From: Sasha Levin <sashal@kernel.org>
-Date: Tue, 20 Apr 2021 00:56:10 -0500
-Subject: um: Fix stack pointer alignment
-
-From: YiFei Zhu <zhuyifei1999@gmail.com>
-
-[ Upstream commit 558f9b2f94dbd2d5c5c8292aa13e081cc11ea7d9 ]
-
-GCC assumes that stack is aligned to 16-byte on call sites [1].
-Since GCC 8, GCC began using 16-byte aligned SSE instructions to
-implement assignments to structs on stack. When
-CC_OPTIMIZE_FOR_PERFORMANCE is enabled, this affects
-os-Linux/sigio.c, write_sigio_thread:
-
-  struct pollfds *fds, tmp;
-  tmp = current_poll;
-
-Note that struct pollfds is exactly 16 bytes in size.
-GCC 8+ generates assembly similar to:
-
-  movdqa (%rdi),%xmm0
-  movaps %xmm0,-0x50(%rbp)
-
-This is an issue, because movaps will #GP if -0x50(%rbp) is not
-aligned to 16 bytes [2], and how rbp gets assigned to is via glibc
-clone thread_start, then function prologue, going though execution
-trace similar to (showing only relevant instructions):
-
-  sub    $0x10,%rsi
-  mov    %rcx,0x8(%rsi)
-  mov    %rdi,(%rsi)
-  syscall
-  pop    %rax
-  pop    %rdi
-  callq  *%rax
-  push   %rbp
-  mov    %rsp,%rbp
-
-The stack pointer always points to the topmost element on stack,
-rather then the space right above the topmost. On push, the
-pointer decrements first before writing to the memory pointed to
-by it. Therefore, there is no need to have the stack pointer
-pointer always point to valid memory unless the stack is poped;
-so the `- sizeof(void *)` in the code is unnecessary.
-
-On the other hand, glibc reserves the 16 bytes it needs on stack
-and pops itself, so by the call instruction the stack pointer
-is exactly the caller-supplied sp. It then push the 16 bytes of
-the return address and the saved stack pointer, so the base
-pointer will be 16-byte aligned if and only if the caller
-supplied sp is 16-byte aligned. Therefore, the caller must supply
-a 16-byte aligned pointer, which `stack + UM_KERN_PAGE_SIZE`
-already satisfies.
-
-On a side note, musl is unaffected by this issue because it forces
-16 byte alignment via `and $-16,%rsi` in its clone wrapper.
-Similarly, glibc i386 is also unaffected because it has
-`andl $0xfffffff0, %ecx`.
-
-To reproduce this bug, enable CONFIG_UML_RTC and
-CC_OPTIMIZE_FOR_PERFORMANCE. uml_rtc will call
-add_sigio_fd which will then cause write_sigio_thread to either go
-into segfault loop or panic with "Segfault with no mm".
-
-Similarly, signal stacks will be aligned by the host kernel upon
-signal delivery. `- sizeof(void *)` to sigaltstack is
-unconventional and extraneous.
-
-On a related note, initialization of longjmp buffers do require
-`- sizeof(void *)`. This is to account for the return address
-that would have been pushed to the stack at the call site.
-
-The reason for uml to respect 16-byte alignment, rather than
-telling GCC to assume 8-byte alignment like the host kernel since
-commit d9b0cde91c60 ("x86-64, gcc: Use
--mpreferred-stack-boundary=3 if supported"), is because uml links
-against libc. There is no reason to assume libc is also compiled
-with that flag and assumes 8-byte alignment rather than 16-byte.
-
-[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=40838
-[2] https://c9x.me/x86/html/file_module_x86_id_180.html
-
-Signed-off-by: YiFei Zhu <zhuyifei1999@gmail.com>
-Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
-Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
-Signed-off-by: Richard Weinberger <richard@nod.at>
-Signed-off-by: Sasha Levin <sashal@kernel.org>
----
- arch/um/drivers/ubd_kern.c      | 3 +--
- arch/um/kernel/skas/clone.c     | 2 +-
- arch/um/os-Linux/helper.c       | 4 ++--
- arch/um/os-Linux/signal.c       | 2 +-
- arch/um/os-Linux/skas/process.c | 2 +-
- 5 files changed, 6 insertions(+), 7 deletions(-)
-
-diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
-index b12c1b0d3e1d..13cd435df60d 100644
---- a/arch/um/drivers/ubd_kern.c
-+++ b/arch/um/drivers/ubd_kern.c
-@@ -1196,8 +1196,7 @@ static int __init ubd_driver_init(void){
-                * enough. So use anyway the io thread. */
-       }
-       stack = alloc_stack(0, 0);
--      io_pid = start_io_thread(stack + PAGE_SIZE - sizeof(void *),
--                               &thread_fd);
-+      io_pid = start_io_thread(stack + PAGE_SIZE, &thread_fd);
-       if(io_pid < 0){
-               printk(KERN_ERR
-                      "ubd : Failed to start I/O thread (errno = %d) - "
-diff --git a/arch/um/kernel/skas/clone.c b/arch/um/kernel/skas/clone.c
-index 7c592c788cbf..939f8e28d812 100644
---- a/arch/um/kernel/skas/clone.c
-+++ b/arch/um/kernel/skas/clone.c
-@@ -29,7 +29,7 @@ stub_clone_handler(void)
-       long err;
- 
-       err = stub_syscall2(__NR_clone, CLONE_PARENT | CLONE_FILES | SIGCHLD,
--                          (unsigned long)data + UM_KERN_PAGE_SIZE / 2 - sizeof(void *));
-+                          (unsigned long)data + UM_KERN_PAGE_SIZE / 2);
-       if (err) {
-               data->parent_err = err;
-               goto done;
-diff --git a/arch/um/os-Linux/helper.c b/arch/um/os-Linux/helper.c
-index 9fa6e4187d4f..32e88baf18dd 100644
---- a/arch/um/os-Linux/helper.c
-+++ b/arch/um/os-Linux/helper.c
-@@ -64,7 +64,7 @@ int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv)
-               goto out_close;
-       }
- 
--      sp = stack + UM_KERN_PAGE_SIZE - sizeof(void *);
-+      sp = stack + UM_KERN_PAGE_SIZE;
-       data.pre_exec = pre_exec;
-       data.pre_data = pre_data;
-       data.argv = argv;
-@@ -120,7 +120,7 @@ int run_helper_thread(int (*proc)(void *), void *arg, unsigned int flags,
-       if (stack == 0)
-               return -ENOMEM;
- 
--      sp = stack + UM_KERN_PAGE_SIZE - sizeof(void *);
-+      sp = stack + UM_KERN_PAGE_SIZE;
-       pid = clone(proc, (void *) sp, flags, arg);
-       if (pid < 0) {
-               err = -errno;
-diff --git a/arch/um/os-Linux/signal.c b/arch/um/os-Linux/signal.c
-index b58bc68cbe64..da7145088017 100644
---- a/arch/um/os-Linux/signal.c
-+++ b/arch/um/os-Linux/signal.c
-@@ -129,7 +129,7 @@ void set_sigstack(void *sig_stack, int size)
-       stack_t stack = {
-               .ss_flags = 0,
-               .ss_sp = sig_stack,
--              .ss_size = size - sizeof(void *)
-+              .ss_size = size
-       };
- 
-       if (sigaltstack(&stack, NULL) != 0)
-diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
-index 21c608561363..92918a04440b 100644
---- a/arch/um/os-Linux/skas/process.c
-+++ b/arch/um/os-Linux/skas/process.c
-@@ -280,7 +280,7 @@ int start_userspace(unsigned long stub_stack)
-       }
- 
-       /* set stack pointer to the end of the stack page, so it can grow downwards */
--      sp = (unsigned long) stack + UM_KERN_PAGE_SIZE - sizeof(void *);
-+      sp = (unsigned long)stack + UM_KERN_PAGE_SIZE;
- 
-       flags = CLONE_FILES | SIGCHLD;
- 
--- 
-2.30.2
-