enderice2/Fennix
enderice2/Fennix
1
0
Fork 0
mirror of https://github.com/EnderIce2/Fennix.git synced 2025-05-30 08:17:58 +00:00
Code Issues Actions Releases Wiki Activity

Refactor stack handling in thread.cpp

Browse Source
This commit is contained in:
EnderIce2 2024-03-05 00:30:54 +02:00
parent afd9227f31
commit 3cf4fda68a
Signed by untrusted user who does not match committer: enderice2
GPG Key ID: EACC3AD603BAB4DD
1 changed files with 59 additions and 57 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

116
tasking/thread.cpp
View File

@ -184,71 +184,71 @@ namespace Tasking
const char **envp, const char **envp,
const std::vector<AuxiliaryVector> &auxv) const std::vector<AuxiliaryVector> &auxv)
{ {
size_t ArgvSize = 0; size_t argvLen = 0;
if (argv) if (argv)
while (argv[ArgvSize] != nullptr) while (argv[argvLen] != nullptr)
ArgvSize++; argvLen++;
size_t EnvpSize = 0; size_t envpLen = 0;
if (envp) if (envp)
while (envp[EnvpSize] != nullptr) while (envp[envpLen] != nullptr)
EnvpSize++; envpLen++;
debug("ArgvSize: %d", ArgvSize); debug("argvLen: %d", argvLen);
debug("EnvpSize: %d", EnvpSize); debug("envpLen: %d", envpLen);
/* https://articles.manugarg.com/aboutelfauxiliaryvectors.html */ /* https://articles.manugarg.com/aboutelfauxiliaryvectors.html */
/* https://refspecs.linuxbase.org/elf/x86_64-abi-0.99.pdf#figure.3.9 */ /* https://refspecs.linuxbase.org/elf/x86_64-abi-0.99.pdf#figure.3.9 */
/* rsp is the top of the stack */ /* rsp is the top of the stack */
char *Stack = (char *)this->Stack->GetStackPhysicalTop(); char *pStack = (char *)this->Stack->GetStackPhysicalTop();
/* Temporary stack pointer for strings */ /* Temporary stack pointer for strings */
char *StackStrings = (char *)Stack; char *stackStr = (char *)pStack;
char *StackStringsVirtual = (char *)this->Stack->GetStackTop(); char *stackStrVirtual = (char *)this->Stack->GetStackTop();
/* Store string pointers for later */ /* Store string pointers for later */
uintptr_t *ArgvStrings = nullptr; uintptr_t *argvStrings = nullptr;
uintptr_t *EnvpStrings = nullptr; uintptr_t *envpStrings = nullptr;
if (ArgvSize > 0) if (argvLen > 0)
ArgvStrings = new uintptr_t[ArgvSize]; argvStrings = new uintptr_t[argvLen];
if (EnvpSize > 0) if (envpLen > 0)
EnvpStrings = new uintptr_t[EnvpSize]; envpStrings = new uintptr_t[envpLen];
for (size_t i = 0; i < ArgvSize; i++) for (size_t i = 0; i < argvLen; i++)
{ {
/* Subtract the length of the string and the null terminator */ /* Subtract the length of the string and the null terminator */
StackStrings -= strlen(argv[i]) + 1; stackStr -= strlen(argv[i]) + 1;
StackStringsVirtual -= strlen(argv[i]) + 1; stackStrVirtual -= strlen(argv[i]) + 1;
/* Store the pointer to the string */ /* Store the pointer to the string */
ArgvStrings[i] = (uintptr_t)StackStringsVirtual; argvStrings[i] = (uintptr_t)stackStrVirtual;
/* Copy the string to the stack */ /* Copy the string to the stack */
strcpy(StackStrings, argv[i]); strcpy(stackStr, argv[i]);
debug("argv[%d]: %s", i, argv[i]); debug("argv[%d]: %s", i, argv[i]);
} }
for (size_t i = 0; i < EnvpSize; i++) for (size_t i = 0; i < envpLen; i++)
{ {
/* Subtract the length of the string and the null terminator */ /* Subtract the length of the string and the null terminator */
StackStrings -= strlen(envp[i]) + 1; stackStr -= strlen(envp[i]) + 1;
StackStringsVirtual -= strlen(envp[i]) + 1; stackStrVirtual -= strlen(envp[i]) + 1;
/* Store the pointer to the string */ /* Store the pointer to the string */
EnvpStrings[i] = (uintptr_t)StackStringsVirtual; envpStrings[i] = (uintptr_t)stackStrVirtual;
/* Copy the string to the stack */ /* Copy the string to the stack */
strcpy(StackStrings, envp[i]); strcpy(stackStr, envp[i]);
debug("envp[%d]: %s", i, envp[i]); debug("envp[%d]: %s", i, envp[i]);
} }
/* Align the stack to 16 bytes */ /* Align the stack to 16 bytes */
StackStrings -= (uintptr_t)StackStrings & 0xF; stackStr -= (uintptr_t)stackStr & 0xF;
/* Set "Stack" to the new stack pointer */ /* Set "pStack" to the new stack pointer */
Stack = (char *)StackStrings; pStack = (char *)stackStr;
/* If argv and envp sizes are odd then we need to align the stack */ /* If argv and envp sizes are odd then we need to align the stack */
Stack -= (ArgvSize + EnvpSize) % 2; pStack -= (argvLen + envpLen) % 2;
debug("odd align: %#lx | %#lx -> %#lx", debug("odd align: %#lx | %#lx -> %#lx",
(ArgvSize + EnvpSize) % 2, (argvLen + envpLen) % 2,
StackStrings, Stack); stackStr, pStack);
/* We need 8 bit pointers for the stack from here */ /* We need 8 bit pointers for the stack from here */
uintptr_t *Stack64 = (uintptr_t *)Stack; uintptr_t *Stack64 = (uintptr_t *)pStack;
assert(Stack64 != nullptr); assert(Stack64 != nullptr);
/* Store the null terminator */ /* Store the null terminator */
@ -273,45 +273,47 @@ namespace Tasking
/* Store the null terminator */ /* Store the null terminator */
StackPush(Stack64, uintptr_t, AT_NULL); StackPush(Stack64, uintptr_t, AT_NULL);
/* Store EnvpStrings[] to the stack */ /* Store envpStrings[] to the stack */
Stack64 -= EnvpSize; /* (1 Stack64 = 8 bits; Stack64 = 8 * EnvpSize) */ Stack64 -= envpLen; /* (1 Stack64 = 8 bits; Stack64 = 8 * envpLen) */
for (size_t i = 0; i < EnvpSize; i++) for (size_t i = 0; i < envpLen; i++)
{ {
*(Stack64 + i) = (uintptr_t)EnvpStrings[i]; *(Stack64 + i) = (uintptr_t)envpStrings[i];
debug("EnvpStrings[%d]: %#lx", debug("envpStrings[%d]: %#lx",
i, EnvpStrings[i]); i, envpStrings[i]);
} }
/* Store the null terminator */ /* Store the null terminator */
StackPush(Stack64, uintptr_t, AT_NULL); StackPush(Stack64, uintptr_t, AT_NULL);
/* Store ArgvStrings[] to the stack */ /* Store argvStrings[] to the stack */
Stack64 -= ArgvSize; /* (1 Stack64 = 8 bits; Stack64 = 8 * ArgvSize) */ Stack64 -= argvLen; /* (1 Stack64 = 8 bits; Stack64 = 8 * argvLen) */
for (size_t i = 0; i < ArgvSize; i++) for (size_t i = 0; i < argvLen; i++)
{ {
*(Stack64 + i) = (uintptr_t)ArgvStrings[i]; *(Stack64 + i) = (uintptr_t)argvStrings[i];
debug("ArgvStrings[%d]: %#lx", debug("argvStrings[%d]: %#lx",
i, ArgvStrings[i]); i, argvStrings[i]);
} }
/* Store the argc */ /* Store the argc */
StackPush(Stack64, uintptr_t, ArgvSize); StackPush(Stack64, uintptr_t, argvLen);
/* Set "Stack" to the new stack pointer */ /* Set "pStack" to the new stack pointer */
Stack = (char *)Stack64; pStack = (char *)Stack64;
/* Ensure StackPointerReg is aligned to the closest lower 16 bytes boundary */
uintptr_t lower16Align = (uintptr_t)pStack;
lower16Align &= ~0xF;
pStack = (char *)lower16Align;
/* We need the virtual address but because we are in the kernel we can't use the process page table. /* We need the virtual address but because we are in the kernel we can't use the process page table.
So we modify the physical address and store how much we need to subtract to get the virtual address for RSP. */ So we modify the physical address and store how much we need to subtract to get the virtual address for RSP. */
uintptr_t SubtractStack = (uintptr_t)this->Stack->GetStackPhysicalTop() - (uintptr_t)Stack; uintptr_t SubtractStack = (uintptr_t)this->Stack->GetStackPhysicalTop() - (uintptr_t)pStack;
debug("SubtractStack: %#lx", SubtractStack); debug("SubtractStack: %#lx", SubtractStack);
/* Set the stack pointer to the new stack */ /* Set the stack pointer to the new stack */
uintptr_t StackPointerReg = ((uintptr_t)this->Stack->GetStackTop() - SubtractStack); uintptr_t StackPointerReg = ((uintptr_t)this->Stack->GetStackTop() - SubtractStack);
// assert(!(StackPointerReg & 0xF)); // assert(!(StackPointerReg & 0xF));
/* Ensure StackPointerReg is aligned to the closest lower 16 bytes boundary */
StackPointerReg &= ~0xF;
#if defined(a64) #if defined(a64)
this->Registers.rsp = StackPointerReg; this->Registers.rsp = StackPointerReg;
#elif defined(a32) #elif defined(a32)
@ -320,10 +322,10 @@ namespace Tasking
this->Registers.sp = StackPointerReg; this->Registers.sp = StackPointerReg;
#endif #endif
if (ArgvSize > 0) if (argvLen > 0)
delete[] ArgvStrings; delete[] argvStrings;
if (EnvpSize > 0) if (envpLen > 0)
delete[] EnvpStrings; delete[] envpStrings;
#ifdef DEBUG #ifdef DEBUG
DumpData("Stack Data", DumpData("Stack Data",