From 4eafad7febd482092b331ea72c37274d745956be Mon Sep 17 00:00:00 2001 From: Alexey Ishchuk Date: Fri, 14 Nov 2014 14:27:58 +0100 Subject: [PATCH] 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 ] Signed-off-by: Alexey Ishchuk Signed-off-by: Martin Schwidefsky --- arch/s390/include/uapi/asm/unistd.h | 4 +- arch/s390/kernel/compat_wrapper.c | 2 + arch/s390/kernel/entry.h | 2 + arch/s390/kernel/syscalls.S | 2 + arch/s390/pci/Makefile | 2 +- arch/s390/pci/pci_mmio.c | 115 ++++++++++++++++++++++++++++ kernel/sys_ni.c | 2 + 7 files changed, 127 insertions(+), 2 deletions(-) create mode 100644 arch/s390/pci/pci_mmio.c diff --git a/arch/s390/include/uapi/asm/unistd.h b/arch/s390/include/uapi/asm/unistd.h index 4197c89c52d4..2b446cf0cc65 100644 --- a/arch/s390/include/uapi/asm/unistd.h +++ b/arch/s390/include/uapi/asm/unistd.h @@ -287,7 +287,9 @@ #define __NR_getrandom 349 #define __NR_memfd_create 350 #define __NR_bpf 351 -#define NR_syscalls 352 +#define __NR_s390_pci_mmio_write 352 +#define __NR_s390_pci_mmio_read 353 +#define NR_syscalls 354 /* * There are some system calls that are not present on 64 bit, some diff --git a/arch/s390/kernel/compat_wrapper.c b/arch/s390/kernel/compat_wrapper.c index c4f7a3d655b8..d7fa2f0f1425 100644 --- a/arch/s390/kernel/compat_wrapper.c +++ b/arch/s390/kernel/compat_wrapper.c @@ -218,3 +218,5 @@ COMPAT_SYSCALL_WRAP3(seccomp, unsigned int, op, unsigned int, flags, const char COMPAT_SYSCALL_WRAP3(getrandom, char __user *, buf, size_t, count, unsigned int, flags) COMPAT_SYSCALL_WRAP2(memfd_create, const char __user *, uname, unsigned int, flags) COMPAT_SYSCALL_WRAP3(bpf, int, cmd, union bpf_attr *, attr, unsigned int, size); +COMPAT_SYSCALL_WRAP3(s390_pci_mmio_write, const unsigned long, mmio_addr, const void __user *, user_buffer, const size_t, length); +COMPAT_SYSCALL_WRAP3(s390_pci_mmio_read, const unsigned long, mmio_addr, void __user *, user_buffer, const size_t, length); diff --git a/arch/s390/kernel/entry.h b/arch/s390/kernel/entry.h index 0554b9771c9f..8e61393c8275 100644 --- a/arch/s390/kernel/entry.h +++ b/arch/s390/kernel/entry.h @@ -74,4 +74,6 @@ struct old_sigaction; long sys_s390_personality(unsigned int personality); long sys_s390_runtime_instr(int command, int signum); +long sys_s390_pci_mmio_write(unsigned long, const void __user *, size_t); +long sys_s390_pci_mmio_read(unsigned long, void __user *, size_t); #endif /* _ENTRY_H */ diff --git a/arch/s390/kernel/syscalls.S b/arch/s390/kernel/syscalls.S index 9f7087fd58de..a2987243bc76 100644 --- a/arch/s390/kernel/syscalls.S +++ b/arch/s390/kernel/syscalls.S @@ -360,3 +360,5 @@ SYSCALL(sys_seccomp,sys_seccomp,compat_sys_seccomp) SYSCALL(sys_getrandom,sys_getrandom,compat_sys_getrandom) SYSCALL(sys_memfd_create,sys_memfd_create,compat_sys_memfd_create) /* 350 */ SYSCALL(sys_bpf,sys_bpf,compat_sys_bpf) +SYSCALL(sys_ni_syscall,sys_s390_pci_mmio_write,compat_sys_s390_pci_mmio_write) +SYSCALL(sys_ni_syscall,sys_s390_pci_mmio_read,compat_sys_s390_pci_mmio_read) diff --git a/arch/s390/pci/Makefile b/arch/s390/pci/Makefile index a9e1dc4ae442..805d8b29193a 100644 --- a/arch/s390/pci/Makefile +++ b/arch/s390/pci/Makefile @@ -3,4 +3,4 @@ # obj-$(CONFIG_PCI) += pci.o pci_dma.o pci_clp.o pci_sysfs.o \ - pci_event.o pci_debug.o pci_insn.o + pci_event.o pci_debug.o pci_insn.o pci_mmio.o diff --git a/arch/s390/pci/pci_mmio.c b/arch/s390/pci/pci_mmio.c new file mode 100644 index 000000000000..62c5ea6d8682 --- /dev/null +++ b/arch/s390/pci/pci_mmio.c @@ -0,0 +1,115 @@ +/* + * Access to PCI I/O memory from user space programs. + * + * Copyright IBM Corp. 2014 + * Author(s): Alexey Ishchuk + */ +#include +#include +#include +#include +#include +#include + +static long get_pfn(unsigned long user_addr, unsigned long access, + unsigned long *pfn) +{ + struct vm_area_struct *vma; + long ret; + + down_read(¤t->mm->mmap_sem); + ret = -EINVAL; + vma = find_vma(current->mm, user_addr); + if (!vma) + goto out; + ret = -EACCES; + if (!(vma->vm_flags & access)) + goto out; + ret = follow_pfn(vma, user_addr, pfn); +out: + up_read(¤t->mm->mmap_sem); + return ret; +} + +SYSCALL_DEFINE3(s390_pci_mmio_write, unsigned long, mmio_addr, + const void __user *, user_buffer, size_t, length) +{ + u8 local_buf[64]; + void __iomem *io_addr; + void *buf; + unsigned long pfn; + long ret; + + if (!zpci_is_enabled()) + return -ENODEV; + + if (length <= 0 || PAGE_SIZE - (mmio_addr & ~PAGE_MASK) < length) + return -EINVAL; + if (length > 64) { + buf = kmalloc(length, GFP_KERNEL); + if (!buf) + return -ENOMEM; + } else + buf = local_buf; + + ret = get_pfn(mmio_addr, VM_WRITE, &pfn); + if (ret) + goto out; + io_addr = (void *)((pfn << PAGE_SHIFT) | (mmio_addr & ~PAGE_MASK)); + + ret = -EFAULT; + if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE) + goto out; + + if (copy_from_user(buf, user_buffer, length)) + goto out; + + memcpy_toio(io_addr, buf, length); + ret = 0; +out: + if (buf != local_buf) + kfree(buf); + return ret; +} + +SYSCALL_DEFINE3(s390_pci_mmio_read, unsigned long, mmio_addr, + void __user *, user_buffer, size_t, length) +{ + u8 local_buf[64]; + void __iomem *io_addr; + void *buf; + unsigned long pfn; + long ret; + + if (!zpci_is_enabled()) + return -ENODEV; + + if (length <= 0 || PAGE_SIZE - (mmio_addr & ~PAGE_MASK) < length) + return -EINVAL; + if (length > 64) { + buf = kmalloc(length, GFP_KERNEL); + if (!buf) + return -ENOMEM; + } else + buf = local_buf; + + ret = get_pfn(mmio_addr, VM_READ, &pfn); + if (ret) + goto out; + io_addr = (void *)((pfn << PAGE_SHIFT) | (mmio_addr & ~PAGE_MASK)); + + ret = -EFAULT; + if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE) + goto out; + + memcpy_fromio(buf, io_addr, length); + + if (copy_to_user(user_buffer, buf, length)) + goto out; + + ret = 0; +out: + if (buf != local_buf) + kfree(buf); + return ret; +} diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c index 02aa4185b17e..61eea02b53f5 100644 --- a/kernel/sys_ni.c +++ b/kernel/sys_ni.c @@ -169,6 +169,8 @@ cond_syscall(ppc_rtas); cond_syscall(sys_spu_run); cond_syscall(sys_spu_create); cond_syscall(sys_subpage_prot); +cond_syscall(sys_s390_pci_mmio_read); +cond_syscall(sys_s390_pci_mmio_write); /* mmu depending weak syscall entries */ cond_syscall(sys_mprotect); -- 2.20.1