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s390/kernel: add system calls for PCI memory access

Add the new __NR_s390_pci_mmio_write and __NR_s390_pci_mmio_read system calls to allow user space applications to access device PCI I/O memory pages on s390x platform. [ Martin Schwidefsky: some code beautification ]

Alexey Ishchuk committed 12 years ago

Commit 4eafad71 parent 86c558e7 files · +127 −2Browse files

Unified · Split

7 files
  1. arch/s390/include/uapi/asm/unistd.h +3 −1
  2. arch/s390/kernel/compat_wrapper.c +2 −0
  3. arch/s390/kernel/entry.h +2 −0
  4. arch/s390/kernel/syscalls.S +2 −0
  5. arch/s390/pci/Makefile +1 −1
  6. arch/s390/pci/pci_mmio.c +115 −0
  7. kernel/sys_ni.c +2 −0
arch/s390/include/uapi/asm/unistd.h+3−1
@@ -287,7 +287,9 @@ · 286 unmodified lines
287287 #define __NR_getrandom 349
288288 #define __NR_memfd_create 350
289289 #define __NR_bpf 351
290−#define NR_syscalls 352
290+#define __NR_s390_pci_mmio_write 352
291+#define __NR_s390_pci_mmio_read 353
292+#define NR_syscalls 354
291293
292294 /*
293295 * There are some system calls that are not present on 64 bit, some
arch/s390/kernel/compat_wrapper.c+2−0
@@ -218,3 +218,5 @@ COMPAT_SYSCALL_WRAP3(seccomp, unsigned int, op, unsigned int, flags, const char · 217 unmodified lines
218218 COMPAT_SYSCALL_WRAP3(getrandom, char __user *, buf, size_t, count, unsigned int, flags)
219219 COMPAT_SYSCALL_WRAP2(memfd_create, const char __user *, uname, unsigned int, flags)
220220 COMPAT_SYSCALL_WRAP3(bpf, int, cmd, union bpf_attr *, attr, unsigned int, size);
221+COMPAT_SYSCALL_WRAP3(s390_pci_mmio_write, const unsigned long, mmio_addr, const void __user *, user_buffer, const size_t, length);
222+COMPAT_SYSCALL_WRAP3(s390_pci_mmio_read, const unsigned long, mmio_addr, void __user *, user_buffer, const size_t, length);
arch/s390/kernel/entry.h+2−0
@@ -74,4 +74,6 @@ struct old_sigaction; · 73 unmodified lines
7474 long sys_s390_personality(unsigned int personality);
7575 long sys_s390_runtime_instr(int command, int signum);
7676
77+long sys_s390_pci_mmio_write(unsigned long, const void __user *, size_t);
78+long sys_s390_pci_mmio_read(unsigned long, void __user *, size_t);
7779 #endif /* _ENTRY_H */
arch/s390/kernel/syscalls.S+2−0
@@ -360,3 +360,5 @@ SYSCALL(sys_seccomp,sys_seccomp,compat_sys_seccomp) · 359 unmodified lines
360360 SYSCALL(sys_getrandom,sys_getrandom,compat_sys_getrandom)
361361 SYSCALL(sys_memfd_create,sys_memfd_create,compat_sys_memfd_create) /* 350 */
362362 SYSCALL(sys_bpf,sys_bpf,compat_sys_bpf)
363+SYSCALL(sys_ni_syscall,sys_s390_pci_mmio_write,compat_sys_s390_pci_mmio_write)
364+SYSCALL(sys_ni_syscall,sys_s390_pci_mmio_read,compat_sys_s390_pci_mmio_read)
arch/s390/pci/Makefile+1−1
@@ -3,4 +3,4 @@ · 2 unmodified lines
33 #
44
55 obj-$(CONFIG_PCI) += pci.o pci_dma.o pci_clp.o pci_sysfs.o \
6− pci_event.o pci_debug.o pci_insn.o
6+ pci_event.o pci_debug.o pci_insn.o pci_mmio.o
arch/s390/pci/pci_mmio.c+115−0
@@ -0,0 +1,115 @@
1+/*
2+ * Access to PCI I/O memory from user space programs.
3+ *
4+ * Copyright IBM Corp. 2014
5+ * Author(s): Alexey Ishchuk <aishchuk@linux.vnet.ibm.com>
6+ */
7+#include <linux/kernel.h>
8+#include <linux/syscalls.h>
9+#include <linux/init.h>
10+#include <linux/mm.h>
11+#include <linux/errno.h>
12+#include <linux/pci.h>
13+
14+static long get_pfn(unsigned long user_addr, unsigned long access,
15+ unsigned long *pfn)
16+{
17+ struct vm_area_struct *vma;
18+ long ret;
19+
20+ down_read(&current->mm->mmap_sem);
21+ ret = -EINVAL;
22+ vma = find_vma(current->mm, user_addr);
23+ if (!vma)
24+ goto out;
25+ ret = -EACCES;
26+ if (!(vma->vm_flags & access))
27+ goto out;
28+ ret = follow_pfn(vma, user_addr, pfn);
29+out:
30+ up_read(&current->mm->mmap_sem);
31+ return ret;
32+}
33+
34+SYSCALL_DEFINE3(s390_pci_mmio_write, unsigned long, mmio_addr,
35+ const void __user *, user_buffer, size_t, length)
36+{
37+ u8 local_buf[64];
38+ void __iomem *io_addr;
39+ void *buf;
40+ unsigned long pfn;
41+ long ret;
42+
43+ if (!zpci_is_enabled())
44+ return -ENODEV;
45+
46+ if (length <= 0 || PAGE_SIZE - (mmio_addr & ~PAGE_MASK) < length)
47+ return -EINVAL;
48+ if (length > 64) {
49+ buf = kmalloc(length, GFP_KERNEL);
50+ if (!buf)
51+ return -ENOMEM;
52+ } else
53+ buf = local_buf;
54+
55+ ret = get_pfn(mmio_addr, VM_WRITE, &pfn);
56+ if (ret)
57+ goto out;
58+ io_addr = (void *)((pfn << PAGE_SHIFT) | (mmio_addr & ~PAGE_MASK));
59+
60+ ret = -EFAULT;
61+ if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE)
62+ goto out;
63+
64+ if (copy_from_user(buf, user_buffer, length))
65+ goto out;
66+
67+ memcpy_toio(io_addr, buf, length);
68+ ret = 0;
69+out:
70+ if (buf != local_buf)
71+ kfree(buf);
72+ return ret;
73+}
74+
75+SYSCALL_DEFINE3(s390_pci_mmio_read, unsigned long, mmio_addr,
76+ void __user *, user_buffer, size_t, length)
77+{
78+ u8 local_buf[64];
79+ void __iomem *io_addr;
80+ void *buf;
81+ unsigned long pfn;
82+ long ret;
83+
84+ if (!zpci_is_enabled())
85+ return -ENODEV;
86+
87+ if (length <= 0 || PAGE_SIZE - (mmio_addr & ~PAGE_MASK) < length)
88+ return -EINVAL;
89+ if (length > 64) {
90+ buf = kmalloc(length, GFP_KERNEL);
91+ if (!buf)
92+ return -ENOMEM;
93+ } else
94+ buf = local_buf;
95+
96+ ret = get_pfn(mmio_addr, VM_READ, &pfn);
97+ if (ret)
98+ goto out;
99+ io_addr = (void *)((pfn << PAGE_SHIFT) | (mmio_addr & ~PAGE_MASK));
100+
101+ ret = -EFAULT;
102+ if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE)
103+ goto out;
104+
105+ memcpy_fromio(buf, io_addr, length);
106+
107+ if (copy_to_user(user_buffer, buf, length))
108+ goto out;
109+
110+ ret = 0;
111+out:
112+ if (buf != local_buf)
113+ kfree(buf);
114+ return ret;
115+}
kernel/sys_ni.c+2−0
@@ -169,6 +169,8 @@ cond_syscall(ppc_rtas); · 168 unmodified lines
169169 cond_syscall(sys_spu_run);
170170 cond_syscall(sys_spu_create);
171171 cond_syscall(sys_subpage_prot);
172+cond_syscall(sys_s390_pci_mmio_read);
173+cond_syscall(sys_s390_pci_mmio_write);
172174
173175 /* mmu depending weak syscall entries */
174176 cond_syscall(sys_mprotect);