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Message-ID: <7663e05099b914d3b978a521b2d3f67791a3abe9.1745980082.git.thehajime@gmail.com>
Date: Wed, 30 Apr 2025 13:27:08 +0900
From: Hajime Tazaki <thehajime@...il.com>
To: linux-um@...ts.infradead.org
Cc: thehajime@...il.com,
ricarkol@...gle.com,
Liam.Howlett@...cle.com,
linux-kernel@...r.kernel.org
Subject: [PATCH v8 02/12] um: decouple MMU specific code from the common part
This splits the memory, process related code with common and MMU
specific parts in order to avoid ifdefs in .c file and duplication
between MMU and !MMU.
Signed-off-by: Hajime Tazaki <thehajime@...il.com>
---
arch/um/kernel/Makefile | 5 +-
arch/um/kernel/mem-pgtable.c | 55 +++++++++++++
arch/um/kernel/mem.c | 35 ---------
arch/um/kernel/process.c | 25 ++++++
arch/um/kernel/skas/process.c | 27 -------
arch/um/os-Linux/Makefile | 3 +-
arch/um/os-Linux/internal.h | 5 ++
arch/um/os-Linux/process.c | 133 ++++++++++++++++++++++++++++++++
arch/um/os-Linux/skas/process.c | 132 -------------------------------
9 files changed, 223 insertions(+), 197 deletions(-)
create mode 100644 arch/um/kernel/mem-pgtable.c
diff --git a/arch/um/kernel/Makefile b/arch/um/kernel/Makefile
index 4df1cd0d2017..827a7438509d 100644
--- a/arch/um/kernel/Makefile
+++ b/arch/um/kernel/Makefile
@@ -16,9 +16,10 @@ extra-y := vmlinux.lds
obj-y = config.o exec.o exitcode.o irq.o ksyms.o mem.o \
physmem.o process.o ptrace.o reboot.o sigio.o \
- signal.o sysrq.o time.o tlb.o trap.o \
- um_arch.o umid.o kmsg_dump.o capflags.o skas/
+ signal.o sysrq.o time.o \
+ um_arch.o umid.o kmsg_dump.o capflags.o
obj-y += load_file.o
+obj-$(CONFIG_MMU) += mem-pgtable.o tlb.o trap.o skas/
obj-$(CONFIG_BLK_DEV_INITRD) += initrd.o
obj-$(CONFIG_GPROF) += gprof_syms.o
diff --git a/arch/um/kernel/mem-pgtable.c b/arch/um/kernel/mem-pgtable.c
new file mode 100644
index 000000000000..549da1d3bff0
--- /dev/null
+++ b/arch/um/kernel/mem-pgtable.c
@@ -0,0 +1,55 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2000 - 2007 Jeff Dike (jdike@...dtoit,linux.intel}.com)
+ */
+
+#include <linux/stddef.h>
+#include <linux/module.h>
+#include <linux/memblock.h>
+#include <linux/swap.h>
+#include <linux/slab.h>
+#include <asm/page.h>
+#include <asm/pgalloc.h>
+#include <as-layout.h>
+#include <init.h>
+#include <kern.h>
+#include <kern_util.h>
+#include <mem_user.h>
+#include <os.h>
+#include <um_malloc.h>
+
+
+/* Allocate and free page tables. */
+
+pgd_t *pgd_alloc(struct mm_struct *mm)
+{
+ pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL);
+
+ if (pgd) {
+ memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
+ memcpy(pgd + USER_PTRS_PER_PGD,
+ swapper_pg_dir + USER_PTRS_PER_PGD,
+ (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
+ }
+ return pgd;
+}
+
+static const pgprot_t protection_map[16] = {
+ [VM_NONE] = PAGE_NONE,
+ [VM_READ] = PAGE_READONLY,
+ [VM_WRITE] = PAGE_COPY,
+ [VM_WRITE | VM_READ] = PAGE_COPY,
+ [VM_EXEC] = PAGE_READONLY,
+ [VM_EXEC | VM_READ] = PAGE_READONLY,
+ [VM_EXEC | VM_WRITE] = PAGE_COPY,
+ [VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY,
+ [VM_SHARED] = PAGE_NONE,
+ [VM_SHARED | VM_READ] = PAGE_READONLY,
+ [VM_SHARED | VM_WRITE] = PAGE_SHARED,
+ [VM_SHARED | VM_WRITE | VM_READ] = PAGE_SHARED,
+ [VM_SHARED | VM_EXEC] = PAGE_READONLY,
+ [VM_SHARED | VM_EXEC | VM_READ] = PAGE_READONLY,
+ [VM_SHARED | VM_EXEC | VM_WRITE] = PAGE_SHARED,
+ [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_SHARED
+};
+DECLARE_VM_GET_PAGE_PROT
diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c
index 61b5a5ede01c..cbe8b9d03d8c 100644
--- a/arch/um/kernel/mem.c
+++ b/arch/um/kernel/mem.c
@@ -6,7 +6,6 @@
#include <linux/stddef.h>
#include <linux/module.h>
#include <linux/memblock.h>
-#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/slab.h>
#include <linux/init.h>
@@ -206,45 +205,11 @@ void free_initmem(void)
{
}
-/* Allocate and free page tables. */
-
-pgd_t *pgd_alloc(struct mm_struct *mm)
-{
- pgd_t *pgd = __pgd_alloc(mm, 0);
-
- if (pgd)
- memcpy(pgd + USER_PTRS_PER_PGD,
- swapper_pg_dir + USER_PTRS_PER_PGD,
- (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
-
- return pgd;
-}
-
void *uml_kmalloc(int size, int flags)
{
return kmalloc(size, flags);
}
-static const pgprot_t protection_map[16] = {
- [VM_NONE] = PAGE_NONE,
- [VM_READ] = PAGE_READONLY,
- [VM_WRITE] = PAGE_COPY,
- [VM_WRITE | VM_READ] = PAGE_COPY,
- [VM_EXEC] = PAGE_READONLY,
- [VM_EXEC | VM_READ] = PAGE_READONLY,
- [VM_EXEC | VM_WRITE] = PAGE_COPY,
- [VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY,
- [VM_SHARED] = PAGE_NONE,
- [VM_SHARED | VM_READ] = PAGE_READONLY,
- [VM_SHARED | VM_WRITE] = PAGE_SHARED,
- [VM_SHARED | VM_WRITE | VM_READ] = PAGE_SHARED,
- [VM_SHARED | VM_EXEC] = PAGE_READONLY,
- [VM_SHARED | VM_EXEC | VM_READ] = PAGE_READONLY,
- [VM_SHARED | VM_EXEC | VM_WRITE] = PAGE_SHARED,
- [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_SHARED
-};
-DECLARE_VM_GET_PAGE_PROT
-
void mark_rodata_ro(void)
{
unsigned long rodata_start = PFN_ALIGN(__start_rodata);
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index 0cd6fad3d908..08959745c30d 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -25,6 +25,7 @@
#include <linux/tick.h>
#include <linux/threads.h>
#include <linux/resume_user_mode.h>
+#include <linux/start_kernel.h>
#include <asm/current.h>
#include <asm/mmu_context.h>
#include <asm/switch_to.h>
@@ -46,6 +47,8 @@
struct task_struct *cpu_tasks[NR_CPUS];
EXPORT_SYMBOL(cpu_tasks);
+static char cpu0_irqstack[THREAD_SIZE] __aligned(THREAD_SIZE);
+
void free_stack(unsigned long stack, int order)
{
free_pages(stack, order);
@@ -295,3 +298,25 @@ unsigned long __get_wchan(struct task_struct *p)
return 0;
}
+
+
+static int __init start_kernel_proc(void *unused)
+{
+ block_signals_trace();
+
+ start_kernel();
+ return 0;
+}
+
+int __init start_uml(void)
+{
+ stack_protections((unsigned long) &cpu0_irqstack);
+ set_sigstack(cpu0_irqstack, THREAD_SIZE);
+
+ init_new_thread_signals();
+
+ init_task.thread.request.thread.proc = start_kernel_proc;
+ init_task.thread.request.thread.arg = NULL;
+ return start_idle_thread(task_stack_page(&init_task),
+ &init_task.thread.switch_buf);
+}
diff --git a/arch/um/kernel/skas/process.c b/arch/um/kernel/skas/process.c
index 05dcdc057af9..5247121d3419 100644
--- a/arch/um/kernel/skas/process.c
+++ b/arch/um/kernel/skas/process.c
@@ -16,33 +16,6 @@
#include <skas.h>
#include <kern_util.h>
-extern void start_kernel(void);
-
-static int __init start_kernel_proc(void *unused)
-{
- block_signals_trace();
-
- start_kernel();
- return 0;
-}
-
-extern int userspace_pid[];
-
-static char cpu0_irqstack[THREAD_SIZE] __aligned(THREAD_SIZE);
-
-int __init start_uml(void)
-{
- stack_protections((unsigned long) &cpu0_irqstack);
- set_sigstack(cpu0_irqstack, THREAD_SIZE);
-
- init_new_thread_signals();
-
- init_task.thread.request.thread.proc = start_kernel_proc;
- init_task.thread.request.thread.arg = NULL;
- return start_idle_thread(task_stack_page(&init_task),
- &init_task.thread.switch_buf);
-}
-
unsigned long current_stub_stack(void)
{
if (current->mm == NULL)
diff --git a/arch/um/os-Linux/Makefile b/arch/um/os-Linux/Makefile
index 049dfa5bc9c6..331564888400 100644
--- a/arch/um/os-Linux/Makefile
+++ b/arch/um/os-Linux/Makefile
@@ -8,7 +8,8 @@ KCOV_INSTRUMENT := n
obj-y = execvp.o file.o helper.o irq.o main.o mem.o process.o \
registers.o sigio.o signal.o start_up.o time.o tty.o \
- umid.o user_syms.o util.o drivers/ skas/
+ umid.o user_syms.o util.o drivers/
+obj-$(CONFIG_MMU) += skas/
CFLAGS_signal.o += -Wframe-larger-than=4096
diff --git a/arch/um/os-Linux/internal.h b/arch/um/os-Linux/internal.h
index 317fca190c2b..bcbf64ce8cd1 100644
--- a/arch/um/os-Linux/internal.h
+++ b/arch/um/os-Linux/internal.h
@@ -2,6 +2,11 @@
#ifndef __UM_OS_LINUX_INTERNAL_H
#define __UM_OS_LINUX_INTERNAL_H
+/*
+ * process.c
+ */
+extern int userspace_pid[];
+
/*
* elf_aux.c
*/
diff --git a/arch/um/os-Linux/process.c b/arch/um/os-Linux/process.c
index 184566edeee9..2331e32c4898 100644
--- a/arch/um/os-Linux/process.c
+++ b/arch/um/os-Linux/process.c
@@ -6,6 +6,7 @@
#include <stdio.h>
#include <stdlib.h>
+#include <stdbool.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>
@@ -15,9 +16,15 @@
#include <sys/prctl.h>
#include <sys/wait.h>
#include <asm/unistd.h>
+#include <linux/threads.h>
#include <init.h>
#include <longjmp.h>
#include <os.h>
+#include <as-layout.h>
+#include <kern_util.h>
+
+int userspace_pid[NR_CPUS];
+int unscheduled_userspace_iterations;
void os_alarm_process(int pid)
{
@@ -158,3 +165,129 @@ void os_set_pdeathsig(void)
{
prctl(PR_SET_PDEATHSIG, SIGKILL);
}
+
+int is_skas_winch(int pid, int fd, void *data)
+{
+ return pid == getpgrp();
+}
+
+void new_thread(void *stack, jmp_buf *buf, void (*handler)(void))
+{
+ (*buf)[0].JB_IP = (unsigned long) handler;
+ (*buf)[0].JB_SP = (unsigned long) stack + UM_THREAD_SIZE -
+ sizeof(void *);
+}
+
+#define INIT_JMP_NEW_THREAD 0
+#define INIT_JMP_CALLBACK 1
+#define INIT_JMP_HALT 2
+#define INIT_JMP_REBOOT 3
+
+void switch_threads(jmp_buf *me, jmp_buf *you)
+{
+ unscheduled_userspace_iterations = 0;
+
+ if (UML_SETJMP(me) == 0)
+ UML_LONGJMP(you, 1);
+}
+
+static jmp_buf initial_jmpbuf;
+
+/* XXX Make these percpu */
+static void (*cb_proc)(void *arg);
+static void *cb_arg;
+static jmp_buf *cb_back;
+
+int start_idle_thread(void *stack, jmp_buf *switch_buf)
+{
+ int n;
+
+ set_handler(SIGWINCH);
+
+ /*
+ * Can't use UML_SETJMP or UML_LONGJMP here because they save
+ * and restore signals, with the possible side-effect of
+ * trying to handle any signals which came when they were
+ * blocked, which can't be done on this stack.
+ * Signals must be blocked when jumping back here and restored
+ * after returning to the jumper.
+ */
+ n = setjmp(initial_jmpbuf);
+ switch (n) {
+ case INIT_JMP_NEW_THREAD:
+ (*switch_buf)[0].JB_IP = (unsigned long) uml_finishsetup;
+ (*switch_buf)[0].JB_SP = (unsigned long) stack +
+ UM_THREAD_SIZE - sizeof(void *);
+ break;
+ case INIT_JMP_CALLBACK:
+ (*cb_proc)(cb_arg);
+ longjmp(*cb_back, 1);
+ break;
+ case INIT_JMP_HALT:
+ kmalloc_ok = 0;
+ return 0;
+ case INIT_JMP_REBOOT:
+ kmalloc_ok = 0;
+ return 1;
+ default:
+ printk(UM_KERN_ERR "Bad sigsetjmp return in %s - %d\n",
+ __func__, n);
+ fatal_sigsegv();
+ }
+ longjmp(*switch_buf, 1);
+
+ /* unreachable */
+ printk(UM_KERN_ERR "impossible long jump!");
+ fatal_sigsegv();
+ return 0;
+}
+
+void initial_thread_cb_skas(void (*proc)(void *), void *arg)
+{
+ jmp_buf here;
+
+ cb_proc = proc;
+ cb_arg = arg;
+ cb_back = &here;
+
+ block_signals_trace();
+ if (UML_SETJMP(&here) == 0)
+ UML_LONGJMP(&initial_jmpbuf, INIT_JMP_CALLBACK);
+ unblock_signals_trace();
+
+ cb_proc = NULL;
+ cb_arg = NULL;
+ cb_back = NULL;
+}
+
+void halt_skas(void)
+{
+ block_signals_trace();
+ UML_LONGJMP(&initial_jmpbuf, INIT_JMP_HALT);
+}
+
+static bool noreboot;
+
+static int __init noreboot_cmd_param(char *str, int *add)
+{
+ *add = 0;
+ noreboot = true;
+ return 0;
+}
+
+__uml_setup("noreboot", noreboot_cmd_param,
+"noreboot\n"
+" Rather than rebooting, exit always, akin to QEMU's -no-reboot option.\n"
+" This is useful if you're using CONFIG_PANIC_TIMEOUT in order to catch\n"
+" crashes in CI\n");
+
+void reboot_skas(void)
+{
+ block_signals_trace();
+ UML_LONGJMP(&initial_jmpbuf, noreboot ? INIT_JMP_HALT : INIT_JMP_REBOOT);
+}
+
+void __switch_mm(struct mm_id *mm_idp)
+{
+ userspace_pid[0] = mm_idp->pid;
+}
diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index ae2aea062f06..40136102fc11 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -5,7 +5,6 @@
*/
#include <stdlib.h>
-#include <stdbool.h>
#include <unistd.h>
#include <sched.h>
#include <errno.h>
@@ -16,7 +15,6 @@
#include <sys/wait.h>
#include <sys/stat.h>
#include <asm/unistd.h>
-#include <as-layout.h>
#include <init.h>
#include <kern_util.h>
#include <mem.h>
@@ -25,15 +23,9 @@
#include <registers.h>
#include <skas.h>
#include <sysdep/stub.h>
-#include <linux/threads.h>
#include <timetravel.h>
#include "../internal.h"
-int is_skas_winch(int pid, int fd, void *data)
-{
- return pid == getpgrp();
-}
-
static const char *ptrace_reg_name(int idx)
{
#define R(n) case HOST_##n: return #n
@@ -315,8 +307,6 @@ static int __init init_stub_exe_fd(void)
}
__initcall(init_stub_exe_fd);
-int userspace_pid[NR_CPUS];
-
/**
* start_userspace() - prepare a new userspace process
* @stub_stack: pointer to the stub stack.
@@ -398,7 +388,6 @@ int start_userspace(unsigned long stub_stack)
return err;
}
-int unscheduled_userspace_iterations;
extern unsigned long tt_extra_sched_jiffies;
void userspace(struct uml_pt_regs *regs)
@@ -560,124 +549,3 @@ void userspace(struct uml_pt_regs *regs)
}
}
}
-
-void new_thread(void *stack, jmp_buf *buf, void (*handler)(void))
-{
- (*buf)[0].JB_IP = (unsigned long) handler;
- (*buf)[0].JB_SP = (unsigned long) stack + UM_THREAD_SIZE -
- sizeof(void *);
-}
-
-#define INIT_JMP_NEW_THREAD 0
-#define INIT_JMP_CALLBACK 1
-#define INIT_JMP_HALT 2
-#define INIT_JMP_REBOOT 3
-
-void switch_threads(jmp_buf *me, jmp_buf *you)
-{
- unscheduled_userspace_iterations = 0;
-
- if (UML_SETJMP(me) == 0)
- UML_LONGJMP(you, 1);
-}
-
-static jmp_buf initial_jmpbuf;
-
-/* XXX Make these percpu */
-static void (*cb_proc)(void *arg);
-static void *cb_arg;
-static jmp_buf *cb_back;
-
-int start_idle_thread(void *stack, jmp_buf *switch_buf)
-{
- int n;
-
- set_handler(SIGWINCH);
-
- /*
- * Can't use UML_SETJMP or UML_LONGJMP here because they save
- * and restore signals, with the possible side-effect of
- * trying to handle any signals which came when they were
- * blocked, which can't be done on this stack.
- * Signals must be blocked when jumping back here and restored
- * after returning to the jumper.
- */
- n = setjmp(initial_jmpbuf);
- switch (n) {
- case INIT_JMP_NEW_THREAD:
- (*switch_buf)[0].JB_IP = (unsigned long) uml_finishsetup;
- (*switch_buf)[0].JB_SP = (unsigned long) stack +
- UM_THREAD_SIZE - sizeof(void *);
- break;
- case INIT_JMP_CALLBACK:
- (*cb_proc)(cb_arg);
- longjmp(*cb_back, 1);
- break;
- case INIT_JMP_HALT:
- kmalloc_ok = 0;
- return 0;
- case INIT_JMP_REBOOT:
- kmalloc_ok = 0;
- return 1;
- default:
- printk(UM_KERN_ERR "Bad sigsetjmp return in %s - %d\n",
- __func__, n);
- fatal_sigsegv();
- }
- longjmp(*switch_buf, 1);
-
- /* unreachable */
- printk(UM_KERN_ERR "impossible long jump!");
- fatal_sigsegv();
- return 0;
-}
-
-void initial_thread_cb_skas(void (*proc)(void *), void *arg)
-{
- jmp_buf here;
-
- cb_proc = proc;
- cb_arg = arg;
- cb_back = &here;
-
- block_signals_trace();
- if (UML_SETJMP(&here) == 0)
- UML_LONGJMP(&initial_jmpbuf, INIT_JMP_CALLBACK);
- unblock_signals_trace();
-
- cb_proc = NULL;
- cb_arg = NULL;
- cb_back = NULL;
-}
-
-void halt_skas(void)
-{
- block_signals_trace();
- UML_LONGJMP(&initial_jmpbuf, INIT_JMP_HALT);
-}
-
-static bool noreboot;
-
-static int __init noreboot_cmd_param(char *str, int *add)
-{
- *add = 0;
- noreboot = true;
- return 0;
-}
-
-__uml_setup("noreboot", noreboot_cmd_param,
-"noreboot\n"
-" Rather than rebooting, exit always, akin to QEMU's -no-reboot option.\n"
-" This is useful if you're using CONFIG_PANIC_TIMEOUT in order to catch\n"
-" crashes in CI\n");
-
-void reboot_skas(void)
-{
- block_signals_trace();
- UML_LONGJMP(&initial_jmpbuf, noreboot ? INIT_JMP_HALT : INIT_JMP_REBOOT);
-}
-
-void __switch_mm(struct mm_id *mm_idp)
-{
- userspace_pid[0] = mm_idp->pid;
-}
--
2.43.0
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