From: benjamin@sipsolutions.net
To: linux-um@lists.infradead.org
Cc: Benjamin Berg <benjamin.berg@intel.com>
Subject: [PATCH 07/12] um: remove copy_context_skas0
Date: Thu, 18 Apr 2024 11:23:22 +0200 [thread overview]
Message-ID: <20240418092327.860135-8-benjamin@sipsolutions.net> (raw)
In-Reply-To: <20240418092327.860135-1-benjamin@sipsolutions.net>
From: Benjamin Berg <benjamin.berg@intel.com>
The kernel flushes the memory ranges anyway for CoW and does not assume
that the userspace process has anything set up already. So, start with a
fresh process for the new mm context.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
---
arch/um/include/shared/os.h | 1 -
arch/um/kernel/skas/Makefile | 8 +--
arch/um/kernel/skas/clone.c | 50 ---------------
arch/um/kernel/skas/mmu.c | 20 +++---
arch/um/os-Linux/skas/process.c | 108 --------------------------------
5 files changed, 10 insertions(+), 177 deletions(-)
delete mode 100644 arch/um/kernel/skas/clone.c
diff --git a/arch/um/include/shared/os.h b/arch/um/include/shared/os.h
index 16d726f3df84..dc341ed4724e 100644
--- a/arch/um/include/shared/os.h
+++ b/arch/um/include/shared/os.h
@@ -281,7 +281,6 @@ void protect(struct mm_id *mm_idp, unsigned long addr,
/* skas/process.c */
extern int is_skas_winch(int pid, int fd, void *data);
extern int start_userspace(unsigned long stub_stack);
-extern int copy_context_skas0(unsigned long stack, int pid);
extern void userspace(struct uml_pt_regs *regs, unsigned long *aux_fp_regs);
extern void new_thread(void *stack, jmp_buf *buf, void (*handler)(void));
extern void switch_threads(jmp_buf *me, jmp_buf *you);
diff --git a/arch/um/kernel/skas/Makefile b/arch/um/kernel/skas/Makefile
index dd8bc2167e36..6f86d53e3d69 100644
--- a/arch/um/kernel/skas/Makefile
+++ b/arch/um/kernel/skas/Makefile
@@ -3,16 +3,14 @@
# Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
#
-obj-y := clone.o stub.o mmu.o process.o syscall.o uaccess.o
+obj-y := stub.o mmu.o process.o syscall.o uaccess.o
-# clone.o and stub.o are in the stub, so it can't be built with profiling
+# stub.o is in the stub, so it can't be built with profiling
# GCC hardened also auto-enables -fpic, but we need %ebx so it can't work ->
# disable it
-CFLAGS_clone.o := $(CFLAGS_NO_HARDENING)
CFLAGS_stub.o := $(CFLAGS_NO_HARDENING)
-UNPROFILE_OBJS := clone.o stub.o
-
+UNPROFILE_OBJS := stub.o
KCOV_INSTRUMENT := n
include $(srctree)/arch/um/scripts/Makefile.rules
diff --git a/arch/um/kernel/skas/clone.c b/arch/um/kernel/skas/clone.c
deleted file mode 100644
index b59fa43d68ce..000000000000
--- a/arch/um/kernel/skas/clone.c
+++ /dev/null
@@ -1,50 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
- * Copyright (C) 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
- */
-
-#include <signal.h>
-#include <sched.h>
-#include <asm/unistd.h>
-#include <sys/time.h>
-#include <as-layout.h>
-#include <ptrace_user.h>
-#include <stub-data.h>
-#include <sysdep/stub.h>
-
-/*
- * This is in a separate file because it needs to be compiled with any
- * extraneous gcc flags (-pg, -fprofile-arcs, -ftest-coverage) disabled
- *
- * Use UM_KERN_PAGE_SIZE instead of PAGE_SIZE because that calls getpagesize
- * on some systems.
- */
-
-void __attribute__ ((__section__ (".__syscall_stub")))
-stub_clone_handler(void)
-{
- struct stub_data *data = get_stub_data();
- long err;
-
- /* syscall data as a temporary stack area (bottom half). */
- err = stub_syscall2(__NR_clone, CLONE_PARENT | CLONE_FILES | SIGCHLD,
- (unsigned long) data->syscall_data +
- sizeof(data->syscall_data) / 2 -
- sizeof(void *));
- if (err) {
- data->err = err;
- goto done;
- }
-
- err = stub_syscall4(__NR_ptrace, PTRACE_TRACEME, 0, 0, 0);
- if (err) {
- data->child_err = err;
- goto done;
- }
-
- remap_stack_and_trap();
-
- done:
- trap_myself();
-}
diff --git a/arch/um/kernel/skas/mmu.c b/arch/um/kernel/skas/mmu.c
index d6183cfd51fe..76c0c7d600a8 100644
--- a/arch/um/kernel/skas/mmu.c
+++ b/arch/um/kernel/skas/mmu.c
@@ -20,8 +20,7 @@ static_assert(sizeof(struct stub_data) == STUB_DATA_PAGES * UM_KERN_PAGE_SIZE);
int init_new_context(struct task_struct *task, struct mm_struct *mm)
{
- struct mm_context *from_mm = NULL;
- struct mm_context *to_mm = &mm->context;
+ struct mm_id *new_id = &mm->context.id;
unsigned long stack = 0;
int ret = -ENOMEM;
@@ -29,27 +28,22 @@ int init_new_context(struct task_struct *task, struct mm_struct *mm)
if (stack == 0)
goto out;
- to_mm->id.stack = stack;
- if (current->mm != NULL && current->mm != &init_mm)
- from_mm = ¤t->mm->context;
+ new_id->stack = stack;
block_signals_trace();
- if (from_mm)
- to_mm->id.u.pid = copy_context_skas0(stack,
- from_mm->id.u.pid);
- else to_mm->id.u.pid = start_userspace(stack);
+ new_id->u.pid = start_userspace(stack);
unblock_signals_trace();
- if (to_mm->id.u.pid < 0) {
- ret = to_mm->id.u.pid;
+ if (new_id->u.pid < 0) {
+ ret = new_id->u.pid;
goto out_free;
}
return 0;
out_free:
- if (to_mm->id.stack != 0)
- free_pages(to_mm->id.stack, ilog2(STUB_DATA_PAGES));
+ if (new_id->stack != 0)
+ free_pages(new_id->stack, ilog2(STUB_DATA_PAGES));
out:
return ret;
}
diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index 2bf03115817c..70c43e4a9cf0 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -460,114 +460,6 @@ void userspace(struct uml_pt_regs *regs, unsigned long *aux_fp_regs)
}
}
-static unsigned long thread_regs[MAX_REG_NR];
-static unsigned long thread_fp_regs[FP_SIZE];
-
-static int __init init_thread_regs(void)
-{
- get_safe_registers(thread_regs, thread_fp_regs);
- /* Set parent's instruction pointer to start of clone-stub */
- thread_regs[REGS_IP_INDEX] = STUB_CODE +
- (unsigned long) stub_clone_handler -
- (unsigned long) __syscall_stub_start;
-
- /* syscall data as a temporary stack area (top half). */
- thread_regs[REGS_SP_INDEX] = STUB_DATA +
- offsetof(struct stub_data, syscall_data) +
- sizeof(((struct stub_data *) 0)->syscall_data) -
- sizeof(void *);
- return 0;
-}
-
-__initcall(init_thread_regs);
-
-int copy_context_skas0(unsigned long new_stack, int pid)
-{
- int err;
- unsigned long current_stack = current_stub_stack();
- struct stub_data *data = (struct stub_data *) current_stack;
- struct stub_data *child_data = (struct stub_data *) new_stack;
- unsigned long long new_offset;
- int new_fd = phys_mapping(uml_to_phys((void *)new_stack), &new_offset);
-
- /*
- * prepare offset and fd of child's stack as argument for parent's
- * and child's mmap2 calls
- */
- *data = ((struct stub_data) {
- .offset = MMAP_OFFSET(new_offset),
- .fd = new_fd,
- .err = -ESRCH,
- .child_err = 0,
- });
-
- *child_data = ((struct stub_data) {
- .child_err = -ESRCH,
- });
-
- err = ptrace_setregs(pid, thread_regs);
- if (err < 0) {
- err = -errno;
- printk(UM_KERN_ERR "%s : PTRACE_SETREGS failed, pid = %d, errno = %d\n",
- __func__, pid, -err);
- return err;
- }
-
- err = put_fp_registers(pid, thread_fp_regs);
- if (err < 0) {
- printk(UM_KERN_ERR "%s : put_fp_registers failed, pid = %d, err = %d\n",
- __func__, pid, err);
- return err;
- }
-
- /*
- * Wait, until parent has finished its work: read child's pid from
- * parent's stack, and check, if bad result.
- */
- err = ptrace(PTRACE_CONT, pid, 0, 0);
- if (err) {
- err = -errno;
- printk(UM_KERN_ERR "Failed to continue new process, pid = %d, errno = %d\n",
- pid, errno);
- return err;
- }
-
- wait_stub_done(pid);
-
- pid = data->err;
- if (pid < 0) {
- printk(UM_KERN_ERR "%s - stub-parent reports error %d\n",
- __func__, -pid);
- return pid;
- }
-
- /*
- * Wait, until child has finished too: read child's result from
- * child's stack and check it.
- */
- wait_stub_done(pid);
- if (child_data->child_err != STUB_DATA) {
- printk(UM_KERN_ERR "%s - stub-child %d reports error %ld\n",
- __func__, pid, data->child_err);
- err = data->child_err;
- goto out_kill;
- }
-
- if (ptrace(PTRACE_SETOPTIONS, pid, NULL,
- (void *)PTRACE_O_TRACESYSGOOD) < 0) {
- err = -errno;
- printk(UM_KERN_ERR "%s : PTRACE_SETOPTIONS failed, errno = %d\n",
- __func__, errno);
- goto out_kill;
- }
-
- return pid;
-
- out_kill:
- os_kill_ptraced_process(pid, 1);
- return err;
-}
-
void new_thread(void *stack, jmp_buf *buf, void (*handler)(void))
{
(*buf)[0].JB_IP = (unsigned long) handler;
--
2.44.0
next prev parent reply other threads:[~2024-04-18 9:25 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-18 9:23 [PATCH 00/12] Rework stub syscall and page table handling benjamin
2024-04-18 9:23 ` [PATCH 01/12] um: Remove stub-data.h include from common-offsets.h benjamin
2024-04-18 9:23 ` [PATCH 02/12] um: Create signal stack memory assignment in stub_data benjamin
2024-04-18 9:23 ` [PATCH 03/12] um: Add generic stub_syscall6 function benjamin
2024-04-18 9:23 ` [PATCH 04/12] um: Rework syscall handling benjamin
2024-04-18 9:23 ` [PATCH 05/12] um: compress memory related stub syscalls while adding them benjamin
2024-04-18 9:23 ` [PATCH 06/12] um: remove LDT support benjamin
2024-04-18 9:23 ` benjamin [this message]
2024-04-18 9:23 ` [PATCH 08/12] um: Delay flushing syscalls until the thread is restarted benjamin
2024-04-18 9:23 ` [PATCH 09/12] um: Do not flush MM in flush_thread benjamin
2024-04-18 9:23 ` [PATCH 10/12] um: remove force_flush_all from fork_handler benjamin
2024-04-18 9:23 ` [PATCH 11/12] um: simplify and consolidate TLB updates benjamin
2024-04-18 9:23 ` [PATCH 12/12] um: refactor TLB update handling benjamin
2024-04-22 2:51 ` Tiwei Bie
2024-04-22 7:22 ` Benjamin Berg
2024-04-22 7:51 ` Anton Ivanov
2024-04-22 2:35 ` [PATCH 00/12] Rework stub syscall and page table handling Tiwei Bie
2024-04-22 7:41 ` Benjamin Berg
2024-04-22 12:08 ` Tiwei Bie
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20240418092327.860135-8-benjamin@sipsolutions.net \
--to=benjamin@sipsolutions.net \
--cc=benjamin.berg@intel.com \
--cc=linux-um@lists.infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.