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minix/kernel/system/do_umap_remote.c

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Split off sys_umap_remote from sys_umap sys_umap now supports only: - looking up the physical address of a virtual address in the address space of the caller; - looking up the physical address of a grant for which the caller is the grantee. This is enough for nearly all umap users. The new sys_umap_remote supports lookups in arbitrary address spaces and grants for arbitrary grantees.
2011-06-10 16:28:20 +02:00
/* The kernel call implemented in this file:
* m_type: SYS_UMAP_REMOTE
*
* The parameters for this kernel call are:
* m5_i1: CP_SRC_PROC_NR (process number)
drop from segments physcopy/vircopy invocations . sys_vircopy always uses D for both src and dst . sys_physcopy uses PHYS_SEG if and only if corresponding endpoint is NONE, so we can derive the mode (PHYS_SEG or D) from the endpoint arg in the kernel, dropping the seg args . fields in msg still filled in for backwards compatability, using same NONE-logic in the library
2012-06-16 19:29:37 +02:00
* m5_s1: UMAP_SEG (segment where address is: T, D, or S)
Split off sys_umap_remote from sys_umap sys_umap now supports only: - looking up the physical address of a virtual address in the address space of the caller; - looking up the physical address of a grant for which the caller is the grantee. This is enough for nearly all umap users. The new sys_umap_remote supports lookups in arbitrary address spaces and grants for arbitrary grantees.
2011-06-10 16:28:20 +02:00
* m5_l1: CP_SRC_ADDR (virtual address)
* m5_i2: CP_DST_ENDPT (process number of grantee to check access for)
* m5_l2: CP_DST_ADDR (returns physical address)
* m5_l3: CP_NR_BYTES (size of datastructure)
*/
#include "kernel/system.h"
#include <minix/endpoint.h>
#if USE_UMAP || USE_UMAP_REMOTE
#if ! USE_UMAP_REMOTE
#undef do_umap_remote
#endif
/*==========================================================================*
* do_umap_remote *
*==========================================================================*/
retire PUBLIC, PRIVATE and FORWARD
2012-03-25 20:25:53 +02:00
int do_umap_remote(struct proc * caller, message * m_ptr)
Split off sys_umap_remote from sys_umap sys_umap now supports only: - looking up the physical address of a virtual address in the address space of the caller; - looking up the physical address of a grant for which the caller is the grantee. This is enough for nearly all umap users. The new sys_umap_remote supports lookups in arbitrary address spaces and grants for arbitrary grantees.
2011-06-10 16:28:20 +02:00
{
/* Map virtual address to physical, for non-kernel processes. */
drop from segments physcopy/vircopy invocations . sys_vircopy always uses D for both src and dst . sys_physcopy uses PHYS_SEG if and only if corresponding endpoint is NONE, so we can derive the mode (PHYS_SEG or D) from the endpoint arg in the kernel, dropping the seg args . fields in msg still filled in for backwards compatability, using same NONE-logic in the library
2012-06-16 19:29:37 +02:00
int seg_type = m_ptr->UMAP_SEG & SEGMENT_TYPE;
int seg_index = m_ptr->UMAP_SEG & SEGMENT_INDEX;
Split off sys_umap_remote from sys_umap sys_umap now supports only: - looking up the physical address of a virtual address in the address space of the caller; - looking up the physical address of a grant for which the caller is the grantee. This is enough for nearly all umap users. The new sys_umap_remote supports lookups in arbitrary address spaces and grants for arbitrary grantees.
2011-06-10 16:28:20 +02:00
vir_bytes offset = m_ptr->CP_SRC_ADDR;
int count = m_ptr->CP_NR_BYTES;
int endpt = (int) m_ptr->CP_SRC_ENDPT;
endpoint_t grantee = (endpoint_t) m_ptr->CP_DST_ENDPT;
retire BIOS_SEG and umap_bios . readbios call is now a physical copy with range check in the kernel call instead of BIOS_SEG+umap_bios . requires all access to physical memory in bios range to go through sys_readbios . drivers/dpeth: wasn't using it . adjusted printer
2012-05-09 18:34:40 +02:00
int proc_nr, proc_nr_grantee;
Split off sys_umap_remote from sys_umap sys_umap now supports only: - looking up the physical address of a virtual address in the address space of the caller; - looking up the physical address of a grant for which the caller is the grantee. This is enough for nearly all umap users. The new sys_umap_remote supports lookups in arbitrary address spaces and grants for arbitrary grantees.
2011-06-10 16:28:20 +02:00
phys_bytes phys_addr = 0, lin_addr = 0;
struct proc *targetpr;
/* Verify process number. */
if (endpt == SELF)
Kernel: use okendpt() to resolve stored endpoints This adds an integrity check at very little cost, and should stop Coverity from flagging array overruns on the result.
2012-08-15 10:50:30 +02:00
okendpt(caller->p_endpoint, &proc_nr);
Split off sys_umap_remote from sys_umap sys_umap now supports only: - looking up the physical address of a virtual address in the address space of the caller; - looking up the physical address of a grant for which the caller is the grantee. This is enough for nearly all umap users. The new sys_umap_remote supports lookups in arbitrary address spaces and grants for arbitrary grantees.
2011-06-10 16:28:20 +02:00
else
if (! isokendpt(endpt, &proc_nr))
return(EINVAL);
targetpr = proc_addr(proc_nr);
/* Verify grantee endpoint */
if (grantee == SELF) {
grantee = caller->p_endpoint;
} else if (grantee == NONE ||
grantee == ANY ||
seg_index != MEM_GRANT ||
!isokendpt(grantee, &proc_nr_grantee)) {
return EINVAL;
}
/* See which mapping should be made. */
switch(seg_type) {
case LOCAL_VM_SEG:
if(seg_index == MEM_GRANT) {
vir_bytes newoffset;
endpoint_t newep;
int new_proc_nr;
cp_grant_id_t grant = (cp_grant_id_t) offset;
if(verify_grant(targetpr->p_endpoint, grantee, grant, count,
make vfs & filesystems use failable copying Change the kernel to add features to vircopy and safecopies so that transparent copy fixing won't happen to avoid deadlocks, and such copies fail with EFAULT. Transparently making copying work from filesystems (as normally done by the kernel & VM when copying fails because of missing/readonly memory) is problematic as it can happen that, for file-mapped ranges, that that same filesystem that is blocked on the copy request is needed to satisfy the memory range, leading to deadlock. Dito for VFS itself, if done with a blocking call. This change makes the copying done from a filesystem fail in such cases with EFAULT by VFS adding the CPF_TRY flag to the grants. If a FS call fails with EFAULT, VFS will then request the range to be made available to VM after the FS is unblocked, allowing it to be used to satisfy the range if need be in another VFS thread. Similarly, for datacopies that VFS itself does, it uses the failable vircopy variant and callers use a wrapper that talk to VM if necessary to get the copy to work. . kernel: add CPF_TRY flag to safecopies . kernel: only request writable ranges to VM for the target buffer when copying fails . do copying in VFS TRY-first . some fixes in VM to build SANITYCHECK mode . add regression test for the cases where - a FS system call needs memory mapped in a process that the FS itself must map. - such a range covers more than one file-mapped region. . add 'try' mode to vircopy, physcopy . add flags field to copy kernel call messages . if CP_FLAG_TRY is set, do not transparently try to fix memory ranges . for use by VFS when accessing user buffers to avoid deadlock . remove some obsolete backwards compatability assignments . VFS: let thread scheduling work for VM requests too Allows VFS to make calls to VM while suspending and resuming the currently running thread. Does currently not work for the main thread. . VM: add fix memory range call for use by VFS Change-Id: I295794269cea51a3163519a9cfe5901301d90b32
2014-01-16 14:22:13 +01:00
0, 0, &newoffset, &newep, NULL) != OK) {
Split off sys_umap_remote from sys_umap sys_umap now supports only: - looking up the physical address of a virtual address in the address space of the caller; - looking up the physical address of a grant for which the caller is the grantee. This is enough for nearly all umap users. The new sys_umap_remote supports lookups in arbitrary address spaces and grants for arbitrary grantees.
2011-06-10 16:28:20 +02:00
printf("SYSTEM: do_umap: verify_grant in %s, grant %d, bytes 0x%lx, failed, caller %s\n", targetpr->p_name, offset, count, caller->p_name);
proc_stacktrace(caller);
return EFAULT;
}
if(!isokendpt(newep, &new_proc_nr)) {
printf("SYSTEM: do_umap: isokendpt failed\n");
return EFAULT;
}
/* New lookup. */
offset = newoffset;
targetpr = proc_addr(new_proc_nr);
No more intel/minix segments. This commit removes all traces of Minix segments (the text/data/stack memory map abstraction in the kernel) and significance of Intel segments (hardware segments like CS, DS that add offsets to all addressing before page table translation). This ultimately simplifies the memory layout and addressing and makes the same layout possible on non-Intel architectures. There are only two types of addresses in the world now: virtual and physical; even the kernel and processes have the same virtual address space. Kernel and user processes can be distinguished at a glance as processes won't use 0xF0000000 and above. No static pre-allocated memory sizes exist any more. Changes to booting: . The pre_init.c leaves the kernel and modules exactly as they were left by the bootloader in physical memory . The kernel starts running using physical addressing, loaded at a fixed location given in its linker script by the bootloader. All code and data in this phase are linked to this fixed low location. . It makes a bootstrap pagetable to map itself to a fixed high location (also in linker script) and jumps to the high address. All code and data then use this high addressing. . All code/data symbols linked at the low addresses is prefixed by an objcopy step with __k_unpaged_*, so that that code cannot reference highly-linked symbols (which aren't valid yet) or vice versa (symbols that aren't valid any more). . The two addressing modes are separated in the linker script by collecting the unpaged_*.o objects and linking them with low addresses, and linking the rest high. Some objects are linked twice, once low and once high. . The bootstrap phase passes a lot of information (e.g. free memory list, physical location of the modules, etc.) using the kinfo struct. . After this bootstrap the low-linked part is freed. . The kernel maps in VM into the bootstrap page table so that VM can begin executing. Its first job is to make page tables for all other boot processes. So VM runs before RS, and RS gets a fully dynamic, VM-managed address space. VM gets its privilege info from RS as usual but that happens after RS starts running. . Both the kernel loading VM and VM organizing boot processes happen using the libexec logic. This removes the last reason for VM to still know much about exec() and vm/exec.c is gone. Further Implementation: . All segments are based at 0 and have a 4 GB limit. . The kernel is mapped in at the top of the virtual address space so as not to constrain the user processes. . Processes do not use segments from the LDT at all; there are no segments in the LDT any more, so no LLDT is needed. . The Minix segments T/D/S are gone and so none of the user-space or in-kernel copy functions use them. The copy functions use a process endpoint of NONE to realize it's a physical address, virtual otherwise. . The umap call only makes sense to translate a virtual address to a physical address now. . Segments-related calls like newmap and alloc_segments are gone. . All segments-related translation in VM is gone (vir2map etc). . Initialization in VM is simpler as no moving around is necessary. . VM and all other boot processes can be linked wherever they wish and will be mapped in at the right location by the kernel and VM respectively. Other changes: . The multiboot code is less special: it does not use mb_print for its diagnostics any more but uses printf() as normal, saving the output into the diagnostics buffer, only printing to the screen using the direct print functions if a panic() occurs. . The multiboot code uses the flexible 'free memory map list' style to receive the list of free memory if available. . The kernel determines the memory layout of the processes to a degree: it tells VM where the kernel starts and ends and where the kernel wants the top of the process to be. VM then uses this entire range, i.e. the stack is right at the top, and mmap()ped bits of memory are placed below that downwards, and the break grows upwards. Other Consequences: . Every process gets its own page table as address spaces can't be separated any more by segments. . As all segments are 0-based, there is no distinction between virtual and linear addresses, nor between userspace and kernel addresses. . Less work is done when context switching, leading to a net performance increase. (8% faster on my machine for 'make servers'.) . The layout and configuration of the GDT makes sysenter and syscall possible.
2012-05-07 16:03:35 +02:00
seg_index = VIR_ADDR;
Split off sys_umap_remote from sys_umap sys_umap now supports only: - looking up the physical address of a virtual address in the address space of the caller; - looking up the physical address of a grant for which the caller is the grantee. This is enough for nearly all umap users. The new sys_umap_remote supports lookups in arbitrary address spaces and grants for arbitrary grantees.
2011-06-10 16:28:20 +02:00
}
No more intel/minix segments. This commit removes all traces of Minix segments (the text/data/stack memory map abstraction in the kernel) and significance of Intel segments (hardware segments like CS, DS that add offsets to all addressing before page table translation). This ultimately simplifies the memory layout and addressing and makes the same layout possible on non-Intel architectures. There are only two types of addresses in the world now: virtual and physical; even the kernel and processes have the same virtual address space. Kernel and user processes can be distinguished at a glance as processes won't use 0xF0000000 and above. No static pre-allocated memory sizes exist any more. Changes to booting: . The pre_init.c leaves the kernel and modules exactly as they were left by the bootloader in physical memory . The kernel starts running using physical addressing, loaded at a fixed location given in its linker script by the bootloader. All code and data in this phase are linked to this fixed low location. . It makes a bootstrap pagetable to map itself to a fixed high location (also in linker script) and jumps to the high address. All code and data then use this high addressing. . All code/data symbols linked at the low addresses is prefixed by an objcopy step with __k_unpaged_*, so that that code cannot reference highly-linked symbols (which aren't valid yet) or vice versa (symbols that aren't valid any more). . The two addressing modes are separated in the linker script by collecting the unpaged_*.o objects and linking them with low addresses, and linking the rest high. Some objects are linked twice, once low and once high. . The bootstrap phase passes a lot of information (e.g. free memory list, physical location of the modules, etc.) using the kinfo struct. . After this bootstrap the low-linked part is freed. . The kernel maps in VM into the bootstrap page table so that VM can begin executing. Its first job is to make page tables for all other boot processes. So VM runs before RS, and RS gets a fully dynamic, VM-managed address space. VM gets its privilege info from RS as usual but that happens after RS starts running. . Both the kernel loading VM and VM organizing boot processes happen using the libexec logic. This removes the last reason for VM to still know much about exec() and vm/exec.c is gone. Further Implementation: . All segments are based at 0 and have a 4 GB limit. . The kernel is mapped in at the top of the virtual address space so as not to constrain the user processes. . Processes do not use segments from the LDT at all; there are no segments in the LDT any more, so no LLDT is needed. . The Minix segments T/D/S are gone and so none of the user-space or in-kernel copy functions use them. The copy functions use a process endpoint of NONE to realize it's a physical address, virtual otherwise. . The umap call only makes sense to translate a virtual address to a physical address now. . Segments-related calls like newmap and alloc_segments are gone. . All segments-related translation in VM is gone (vir2map etc). . Initialization in VM is simpler as no moving around is necessary. . VM and all other boot processes can be linked wherever they wish and will be mapped in at the right location by the kernel and VM respectively. Other changes: . The multiboot code is less special: it does not use mb_print for its diagnostics any more but uses printf() as normal, saving the output into the diagnostics buffer, only printing to the screen using the direct print functions if a panic() occurs. . The multiboot code uses the flexible 'free memory map list' style to receive the list of free memory if available. . The kernel determines the memory layout of the processes to a degree: it tells VM where the kernel starts and ends and where the kernel wants the top of the process to be. VM then uses this entire range, i.e. the stack is right at the top, and mmap()ped bits of memory are placed below that downwards, and the break grows upwards. Other Consequences: . Every process gets its own page table as address spaces can't be separated any more by segments. . As all segments are 0-based, there is no distinction between virtual and linear addresses, nor between userspace and kernel addresses. . Less work is done when context switching, leading to a net performance increase. (8% faster on my machine for 'make servers'.) . The layout and configuration of the GDT makes sysenter and syscall possible.
2012-05-07 16:03:35 +02:00
if(seg_index == VIR_ADDR) {
phys_addr = lin_addr = offset;
Split off sys_umap_remote from sys_umap sys_umap now supports only: - looking up the physical address of a virtual address in the address space of the caller; - looking up the physical address of a grant for which the caller is the grantee. This is enough for nearly all umap users. The new sys_umap_remote supports lookups in arbitrary address spaces and grants for arbitrary grantees.
2011-06-10 16:28:20 +02:00
} else {
printf("SYSTEM: bogus seg type 0x%lx\n", seg_index);
return EFAULT;
}
if(!lin_addr) {
printf("SYSTEM:do_umap: umap_local failed\n");
return EFAULT;
}
if(vm_lookup(targetpr, lin_addr, &phys_addr, NULL) != OK) {
printf("SYSTEM:do_umap: vm_lookup failed\n");
return EFAULT;
}
if(phys_addr == 0)
panic("vm_lookup returned zero physical address");
break;
default:
retire BIOS_SEG and umap_bios . readbios call is now a physical copy with range check in the kernel call instead of BIOS_SEG+umap_bios . requires all access to physical memory in bios range to go through sys_readbios . drivers/dpeth: wasn't using it . adjusted printer
2012-05-09 18:34:40 +02:00
printf("umap: peculiar type\n");
return EINVAL;
Split off sys_umap_remote from sys_umap sys_umap now supports only: - looking up the physical address of a virtual address in the address space of the caller; - looking up the physical address of a grant for which the caller is the grantee. This is enough for nearly all umap users. The new sys_umap_remote supports lookups in arbitrary address spaces and grants for arbitrary grantees.
2011-06-10 16:28:20 +02:00
}
Kernel: replace vm_contiguous with vm_lookup_range
2012-03-21 23:46:51 +01:00
if(vm_running && vm_lookup_range(targetpr, lin_addr, NULL, count) != count) {
Split off sys_umap_remote from sys_umap sys_umap now supports only: - looking up the physical address of a virtual address in the address space of the caller; - looking up the physical address of a grant for which the caller is the grantee. This is enough for nearly all umap users. The new sys_umap_remote supports lookups in arbitrary address spaces and grants for arbitrary grantees.
2011-06-10 16:28:20 +02:00
printf("SYSTEM:do_umap: not contiguous\n");
return EFAULT;
}
m_ptr->CP_DST_ADDR = phys_addr;
No more intel/minix segments. This commit removes all traces of Minix segments (the text/data/stack memory map abstraction in the kernel) and significance of Intel segments (hardware segments like CS, DS that add offsets to all addressing before page table translation). This ultimately simplifies the memory layout and addressing and makes the same layout possible on non-Intel architectures. There are only two types of addresses in the world now: virtual and physical; even the kernel and processes have the same virtual address space. Kernel and user processes can be distinguished at a glance as processes won't use 0xF0000000 and above. No static pre-allocated memory sizes exist any more. Changes to booting: . The pre_init.c leaves the kernel and modules exactly as they were left by the bootloader in physical memory . The kernel starts running using physical addressing, loaded at a fixed location given in its linker script by the bootloader. All code and data in this phase are linked to this fixed low location. . It makes a bootstrap pagetable to map itself to a fixed high location (also in linker script) and jumps to the high address. All code and data then use this high addressing. . All code/data symbols linked at the low addresses is prefixed by an objcopy step with __k_unpaged_*, so that that code cannot reference highly-linked symbols (which aren't valid yet) or vice versa (symbols that aren't valid any more). . The two addressing modes are separated in the linker script by collecting the unpaged_*.o objects and linking them with low addresses, and linking the rest high. Some objects are linked twice, once low and once high. . The bootstrap phase passes a lot of information (e.g. free memory list, physical location of the modules, etc.) using the kinfo struct. . After this bootstrap the low-linked part is freed. . The kernel maps in VM into the bootstrap page table so that VM can begin executing. Its first job is to make page tables for all other boot processes. So VM runs before RS, and RS gets a fully dynamic, VM-managed address space. VM gets its privilege info from RS as usual but that happens after RS starts running. . Both the kernel loading VM and VM organizing boot processes happen using the libexec logic. This removes the last reason for VM to still know much about exec() and vm/exec.c is gone. Further Implementation: . All segments are based at 0 and have a 4 GB limit. . The kernel is mapped in at the top of the virtual address space so as not to constrain the user processes. . Processes do not use segments from the LDT at all; there are no segments in the LDT any more, so no LLDT is needed. . The Minix segments T/D/S are gone and so none of the user-space or in-kernel copy functions use them. The copy functions use a process endpoint of NONE to realize it's a physical address, virtual otherwise. . The umap call only makes sense to translate a virtual address to a physical address now. . Segments-related calls like newmap and alloc_segments are gone. . All segments-related translation in VM is gone (vir2map etc). . Initialization in VM is simpler as no moving around is necessary. . VM and all other boot processes can be linked wherever they wish and will be mapped in at the right location by the kernel and VM respectively. Other changes: . The multiboot code is less special: it does not use mb_print for its diagnostics any more but uses printf() as normal, saving the output into the diagnostics buffer, only printing to the screen using the direct print functions if a panic() occurs. . The multiboot code uses the flexible 'free memory map list' style to receive the list of free memory if available. . The kernel determines the memory layout of the processes to a degree: it tells VM where the kernel starts and ends and where the kernel wants the top of the process to be. VM then uses this entire range, i.e. the stack is right at the top, and mmap()ped bits of memory are placed below that downwards, and the break grows upwards. Other Consequences: . Every process gets its own page table as address spaces can't be separated any more by segments. . As all segments are 0-based, there is no distinction between virtual and linear addresses, nor between userspace and kernel addresses. . Less work is done when context switching, leading to a net performance increase. (8% faster on my machine for 'make servers'.) . The layout and configuration of the GDT makes sysenter and syscall possible.
2012-05-07 16:03:35 +02:00
if(phys_addr == 0) {
Split off sys_umap_remote from sys_umap sys_umap now supports only: - looking up the physical address of a virtual address in the address space of the caller; - looking up the physical address of a grant for which the caller is the grantee. This is enough for nearly all umap users. The new sys_umap_remote supports lookups in arbitrary address spaces and grants for arbitrary grantees.
2011-06-10 16:28:20 +02:00
printf("kernel: umap 0x%x done by %d / %s, pc 0x%lx, 0x%lx -> 0x%lx\n",
seg_type, caller->p_endpoint, caller->p_name,
caller->p_reg.pc, offset, phys_addr);
printf("caller stack: ");
proc_stacktrace(caller);
}
return (phys_addr == 0) ? EFAULT: OK;
}
#endif /* USE_UMAP || USE_UMAP_REMOTE */
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