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Initial work on swapping page tables per process

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This commit is contained in:
Justin C. Miller
2018-08-27 09:09:56 -07:00
parent 1664566bd2
commit 647801f096
4 changed files with 97 additions and 46 deletions
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59
src/kernel/page_manager.h
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@@ -26,13 +26,46 @@ public:
/// Offset from physical where page tables are mapped.
static const addr_t page_offset = 0xffffff8000000000;
/// Initial process thread's stack address
static const addr_t initial_stack = 0x0000800000000000;
/// Initial process thread's stack size, in pages
static const unsigned initial_stack_pages = 1;
page_manager();
/// Helper to read the PML4 table from CR3.
/// \returns A pointer to the current PML4 table.
static inline page_table * get_pml4()
{
addr_t pml4 = 0;
__asm__ __volatile__ ( "mov %%cr3, %0" : "=r" (pml4) );
return reinterpret_cast<page_table *>((pml4 & ~0xfffull) + page_offset);
}
/// Helper to set the PML4 table pointer in CR3.
/// \arg pml4 A pointer to the PML4 table to install.
static inline void set_pml4(page_table *pml4)
{
addr_t p = reinterpret_cast<addr_t>(pml4) - page_offset;
__asm__ __volatile__ ( "mov %0, %%cr3" :: "r" (p & ~0xfffull) );
}
/// Allocate but don't switch to a new PML4 table. This table
/// should only have global kernel pages mapped.
/// \returns A pointer to the PML4 table
page_table * create_process_map();
/// Deallocate a process' PML4 table.
void delete_process_map(page_table *table);
/// Allocate and map pages into virtual memory.
/// \arg address The virtual address at which to map the pages
/// \arg count The number of pages to map
/// \arg user True is this memory is user-accessible
/// \arg pml4 The pml4 to map into - null for the current one
/// \returns A pointer to the start of the mapped region
void * map_pages(addr_t address, size_t count);
void * map_pages(addr_t address, size_t count, bool user = false, page_table *pml4 = nullptr);
/// Allocate and map contiguous pages into virtual memory, with
/// a constant offset from their physical address.
@@ -70,8 +103,9 @@ public:
/// Log the current free/used block lists.
void dump_blocks();
/// Dump the current PML4 to the console
void dump_pml4();
/// Dump the given or current PML4 to the console
/// \arg pml4 The page table to use, null for the current one
void dump_pml4(page_table *pml4 = nullptr);
/// Get the system page manager.
/// \returns A pointer to the system page manager
@@ -108,23 +142,6 @@ private:
/// to the cache.
void consolidate_blocks();
/// Helper to read the PML4 table from CR3.
/// \returns A pointer to the current PML4 table.
static inline page_table * get_pml4()
{
addr_t pml4 = 0;
__asm__ __volatile__ ( "mov %%cr3, %0" : "=r" (pml4) );
return reinterpret_cast<page_table *>((pml4 & ~0xfffull) + page_offset);
}
/// Helper to set the PML4 table pointer in CR3.
/// \arg pml4 A pointer to the PML4 table to install.
static inline void set_pml4(page_table *pml4)
{
addr_t p = reinterpret_cast<addr_t>(pml4) - page_offset;
__asm__ __volatile__ ( "mov %0, %%cr3" :: "r" (p & ~0xfffull) );
}
/// Helper function to allocate a new page table. If table entry `i` in
/// table `base` is empty, allocate a new page table and point `base[i]` at
/// it.
@@ -163,6 +180,8 @@ private:
/// \returns The number of pages retrieved
size_t pop_pages(size_t count, addr_t *address);
page_table *m_kernel_pml4; ///< The PML4 of just kernel pages
page_block *m_free; ///< Free pages list
page_block *m_used; ///< In-use pages list