User-land ring buffers.
git-svn-id: svn://kolibrios.org@7967 a494cfbc-eb01-0410-851d-a64ba20cac60
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hidnplayr
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8ac977e2e4
commit
d397ad5154
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@ -1518,3 +1518,72 @@ proc shmem_close stdcall, name:dword
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ret
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endp
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proc user_ring stdcall, size:dword
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locals
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virt_ptr dd ?
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phys_ptr dd ?
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num_pages dd ?
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endl
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; Size must be an exact multiple of pagesize
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mov eax, size
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test eax, PAGE_SIZE-1
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jnz .exit
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; We must have at least one complete page
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shr eax, 12
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jz .exit
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mov [num_pages], eax
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; Allocate double the virtual memory
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mov eax, [size]
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shl eax, 1
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jz .exit
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stdcall user_alloc, eax
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test eax, eax
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jz .exit
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mov [virt_ptr], eax
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; Now allocate physical memory
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stdcall alloc_pages, [num_pages]
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test eax, eax
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jz .exit_free_virt
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mov [phys_ptr], eax
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; Map first half of virtual memory to physical memory
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push ecx esi edi
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mov ecx, [num_pages]
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mov esi, [virt_ptr]
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mov edi, [phys_ptr]
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.loop1:
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stdcall map_page, esi, edi, PG_UWR
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add esi, PAGE_SIZE
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add edi, PAGE_SIZE
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dec ecx
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jnz .loop1
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; Map second half of virtual memory to same physical memory
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mov ecx, [pages]
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mov edi, [phys_ptr]
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.loop2:
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stdcall map_page, esi, edi, PG_UWR
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add esi, PAGE_SIZE
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add edi, PAGE_SIZE
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dec ecx
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jnz .loop2
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pop edi esi ecx
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mov eax, [virt_ptr]
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ret
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.exit_free_virt:
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stdcall user_free, [virt_ptr]
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.exit:
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xor eax, eax
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ret
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endp
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@ -1,6 +1,6 @@
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; ;;
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;; Copyright (C) KolibriOS team 2004-2015. All rights reserved. ;;
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;; Copyright (C) KolibriOS team 2004-2020. All rights reserved. ;;
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;; Distributed under terms of the GNU General Public License ;;
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;; ;;
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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@ -78,7 +78,7 @@ proc alloc_pages stdcall, count:dword
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.find:
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mov edx, [count]
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mov edi, ecx
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.match:
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.match:
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cmp byte [ecx], 0xFF
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jne .next
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dec edx
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@ -86,14 +86,14 @@ proc alloc_pages stdcall, count:dword
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inc ecx
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cmp ecx, ebx
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jb .match
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.out_of_memory:
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.fail:
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.out_of_memory:
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.fail:
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xor eax, eax
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pop edi
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pop ebx
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popfd
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ret
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.next:
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.next:
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inc ecx
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cmp ecx, ebx
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jb .find
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@ -102,7 +102,7 @@ proc alloc_pages stdcall, count:dword
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popfd
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xor eax, eax
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ret
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.ok:
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.ok:
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sub ecx, edi
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inc ecx
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push esi
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@ -1103,7 +1103,7 @@ f68:
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jbe sys_sheduler
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cmp ebx, 11
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jb undefined_syscall
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cmp ebx, 28
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cmp ebx, 29
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ja undefined_syscall
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xor eax, eax
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jmp dword [f68call+ebx*4-11*4]
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@ -1220,6 +1220,11 @@ f68:
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stdcall kernel_free, ebp
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ret
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.29:
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stdcall user_ring, ecx
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mov [esp+SYSCALL_STACK._eax], eax
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ret
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.fail:
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mov [esp+SYSCALL_STACK._eax], eax
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ret
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@ -1245,6 +1250,7 @@ f68call: ; keep this table closer to main code
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dd f68.26 ; user_unmap
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dd f68.27 ; load_file_umode
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dd f68.28 ; loadFileUnicode
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dd f68.29 ; user_ring
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align 4
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proc load_pe_driver stdcall, file:dword, cmdline:dword
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@ -3612,6 +3612,25 @@ Returned value:
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* edx = size of the loaded file, or zero
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Remarks:
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* function loads file and unpacks, if necessary
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======================================================================
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======== Function 68, subfunction 29 - allocate ring memory. =========
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======================================================================
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Parameters:
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* eax = 68 - function number
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* ebx = 29 - subfunction number
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* ecx = required size in bytes
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Returned value:
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* eax = 0 - failed
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* eax = pointer to the allocated ring
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Remarks:
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* The requested size must be an exact multiple of pagesize (4 Kb)
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* The function allocates memory in such a way that you can read and
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write beyond the size of the allocated memory and will reach the
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beginning of the buffer again.
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---------------------- Constants for registers: ----------------------
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eax - SF_SYS_MISC (68)
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ebx - SSF_MEM_ALLOC_RING (29)
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======================================================================
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====================== Function 69 - debugging. ======================
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